Common Core: High School - Algebra : Reasoning with Equations & Inequalities

Study concepts, example questions & explanations for Common Core: High School - Algebra

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All Common Core: High School - Algebra Resources

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Example Questions

Example Question #11 : Solving An Equation Step By Step: Ccss.Math.Content.Hsa Rei.A.1

Solve for \displaystyle x.

\displaystyle 4x-x+5=x+3

Possible Answers:

\displaystyle x=-4

\displaystyle x=-2

\displaystyle x=1

\displaystyle x=-1

\displaystyle x=4

Correct answer:

\displaystyle x=-1

Explanation:

First, combine like terms on the left-hand side of the equation.

\displaystyle 4x-x=3x

Now, the equation is

\displaystyle 3x+5=x+3

From here, subtract \displaystyle x from both sides.

  \displaystyle 3x+5=x+3

\displaystyle -x           \displaystyle -x

___________________

\displaystyle 2x+5=3

Next, subtract five to both sides.

\displaystyle 2x+5=3

       \displaystyle -5   \displaystyle -5

_____________

\displaystyle 2x=-2

Finally, divide both sides of the equation by two.

\displaystyle \frac{2x}{2}=\frac{-2}{2}

\displaystyle x=-1

Example Question #12 : Solving An Equation Step By Step: Ccss.Math.Content.Hsa Rei.A.1

Solve for \displaystyle x.

\displaystyle 5x-5=51-2x

Possible Answers:

\displaystyle x=2

\displaystyle x=-2

\displaystyle x=1

\displaystyle x=-4

\displaystyle x=8

Correct answer:

\displaystyle x=8

Explanation:

To solve for \displaystyle x, first combine like terms by adding \displaystyle 2x to both sides.

\displaystyle 7x-5=51

Next, add \displaystyle 5 to both sides.

\displaystyle 7x=56

From here, divide by \displaystyle 7 to solve for \displaystyle x.

\displaystyle x=8

Example Question #1 : Solve Simple Rational And Radical One Variable Equations, Show Extraneous Solutions: Ccss.Math.Content.Hsa Rei.A.2

Solve for \displaystyle x.

\displaystyle \sqrt{x-2}=1

Possible Answers:

\displaystyle x=2

\displaystyle x=-1

\displaystyle x=1

\displaystyle x=3

\displaystyle x=-3

Correct answer:

\displaystyle x=3

Explanation:

To solve for \displaystyle x, square both terms to cancel out the square root sign on the left-hand side.

\displaystyle (\sqrt{x-2})^2=(1)^2

\displaystyle x-2=1

Next, add two to both sides of the equation.

\displaystyle x-2=1

     \displaystyle +2  \displaystyle +2

_____________

\displaystyle x=3

From here, check for extraneous solutions by substituting the value found for \displaystyle x into the original equation.

\displaystyle \sqrt{x-2}=1

\displaystyle \\ \sqrt{3-2}=1 \\\sqrt{1}=1 \\\pm1=1

Since the square root of one is either positive or negative one, the solution found is verified.

Example Question #2 : Solve Simple Rational And Radical One Variable Equations, Show Extraneous Solutions: Ccss.Math.Content.Hsa Rei.A.2

Solve for \displaystyle x.

\displaystyle 1-\sqrt{x+1}=5

Possible Answers:

\displaystyle x=24

\displaystyle x=16

\displaystyle x=15

\displaystyle x=5

\displaystyle x=4

Correct answer:

\displaystyle x=15

Explanation:

To solve for \displaystyle x, first subtract one from both sides.

    \displaystyle 1-\sqrt{x+1}=5

\displaystyle -1                        \displaystyle -1

____________________

\displaystyle -\sqrt{x+1}=4

From here, divide both sides by negative one.

\displaystyle -\frac{\sqrt{x+1}}{-1}=\frac{4}{-1}

\displaystyle \sqrt{x+1}=-4

Next, square both sides to cancel the square root sign on the left-hand side.

\displaystyle (\sqrt{x+1})^2=(-4)^2

\displaystyle x+1=16

Now, subtract one from both sides to solve for \displaystyle x.

\displaystyle x+1=16

     \displaystyle -1     \displaystyle -1

____________

\displaystyle x=15

Lastly, check for extraneous solutions by substituting the value found for \displaystyle x into the original equation.

\displaystyle 1-\sqrt{x+1}=5

\displaystyle \\1-\sqrt{15+1}=5 \\1-\sqrt{16}=5 \\1-\pm4=5

Thus, the answer is verified.

Example Question #1 : Solve Simple Rational And Radical One Variable Equations, Show Extraneous Solutions: Ccss.Math.Content.Hsa Rei.A.2

Solve for \displaystyle x.

\displaystyle \frac{1}{x}-2=10

Possible Answers:

\displaystyle x=12

\displaystyle x=\frac{1}{12}

\displaystyle x=-12

\displaystyle x=\frac{1}{8}

\displaystyle x=-\frac{1}{12}

Correct answer:

\displaystyle x=\frac{1}{12}

Explanation:

To solve for \displaystyle x, add two to both sides of the equation.

\displaystyle \frac{1}{x}-2=10

     \displaystyle +2     \displaystyle +2

______________

\displaystyle \frac{1}{x}=12

Now, multiply by \displaystyle x on both sides. This will move the variable from the denominator on one side to the numerator of the other side.

\displaystyle x\cdot \frac{1}{x}=12\cdot x

\displaystyle 1=12x

Lastly, divide both sides by twelve.

\displaystyle \frac{1}{12}=\frac{12x}{12}

The twelve in the numerator and the twelve in the denominator cancel out thus, solving for \displaystyle x.

\displaystyle \frac{1}{12}=x

Example Question #473 : High School: Algebra

Solve for \displaystyle x.

\displaystyle \sqrt{x}+4=3

Possible Answers:

\displaystyle x=3

\displaystyle x=-1

\displaystyle x=1

\displaystyle x=5

\displaystyle x=2

Correct answer:

\displaystyle x=1

Explanation:

To solve for \displaystyle x, first subtract four from both sides so all constants are on one side.

\displaystyle \sqrt{x}+4=3

         \displaystyle -4  \displaystyle -4

_____________

\displaystyle \sqrt{x}=-1

Now, square both sides to cancel the square root sign on the left-hand side.

\displaystyle (\sqrt{x})^2=(-1)^2

\displaystyle x=1

Recall that when a negative number is squared the result is always a positive value.

From here, check for extraneous solutions by substituting in the value found for \displaystyle x.

\displaystyle \\\sqrt{x}+4=3 \\\sqrt{1}+4=3 \\\pm1+4=3 \\-1+4=3

Since the square root of a value results in a positive and a negative value, our solution is verified.

Example Question #11 : Reasoning With Equations & Inequalities

Solve for \displaystyle x.

\displaystyle \sqrt{\frac{x}{2}}=6

Possible Answers:

\displaystyle x=24

\displaystyle x=6

\displaystyle x=36

\displaystyle x=-72

\displaystyle x=72

Correct answer:

\displaystyle x=72

Explanation:

To solve for \displaystyle x start by squaring both sides to eliminate the square root sign.

\displaystyle \left( \sqrt{\frac{x}{2}}\right)^2=(6)^2

\displaystyle \frac{x}{2}=36

From here multiply both sides by two. On the left-hand side, the two in the numerator will cancel out the two in the denominator.

\displaystyle 2\cdot \frac{x}{2}=36\cdot 2

\displaystyle x=72

From here, check for extraneous solutions by substituting in the value found for \displaystyle x into the original equation.

\displaystyle \sqrt{\frac{x}{2}}=6

\displaystyle \sqrt{\frac{72}{2}}=6

\displaystyle \sqrt{36}=6

\displaystyle \pm6=6

Thus, the solution is verified.

Example Question #475 : High School: Algebra

Solve for \displaystyle x.

\displaystyle \frac{3}{x}-2=5

Possible Answers:

\displaystyle x=\frac{7}{3}

\displaystyle x=-\frac{3}{7}

\displaystyle x=-\frac{7}{3}

\displaystyle x=\frac{3}{7}

\displaystyle x=21

Correct answer:

\displaystyle x=\frac{3}{7}

Explanation:

To solve for \displaystyle x, first add two to both sides.

\displaystyle \frac{3}{x}-2=5

     \displaystyle +2   \displaystyle +2

____________

\displaystyle \frac{3}{x}=7

From here, multiply both sides by \displaystyle x

\displaystyle x\cdot \frac{3}{x}=7\cdot x

\displaystyle 3=7x

Now divide by seven to solve for \displaystyle x.

\displaystyle \frac{3}{7}=\frac{7x}{7}

The seven in the numerator and seven in the denominator cancel out, thus solving for \displaystyle x.

\displaystyle \frac{3}{7}=x

Example Question #476 : High School: Algebra

Solve for \displaystyle x.

\displaystyle \sqrt{5-x}=2

Possible Answers:

\displaystyle x=0

\displaystyle x=-2

\displaystyle x=2

\displaystyle x=-1

\displaystyle x=1

Correct answer:

\displaystyle x=1

Explanation:

To solve for \displaystyle x, first square both sides of the equation. Squaring a square root sign will cancel them out.

\displaystyle (\sqrt{5-x})^2=(2)^2

\displaystyle 5-x=4

Now, subtract five from both sides to get all constants on one side of the equation while all variables are on the other side of the equation.

   \displaystyle 5-x=4

\displaystyle -5           \displaystyle -5

_____________

\displaystyle -x=-1

From here, divide by negative one on both sides.

\displaystyle \frac{-x}{-1}=\frac{-1}{-1}

\displaystyle x=1

Lastly, check for extraneous solutions by substituting in the value found for \displaystyle x into the original equation.

\displaystyle \\\sqrt{5-1}=2 \\\sqrt{4}=2 \\\pm2=2

Thus, the solution is verified.

Example Question #477 : High School: Algebra

Solve for \displaystyle x.

\displaystyle \frac{x}{2}=8

Possible Answers:

\displaystyle x=2

\displaystyle x=4

\displaystyle x=16

\displaystyle x=6

\displaystyle x=8

Correct answer:

\displaystyle x=16

Explanation:

To solve for \displaystyle x, simply multiply both sides of the equation by two.

\displaystyle \frac{x}{2}=8

\displaystyle 2\cdot \frac{x}{2}=8\cdot 2

The two in the numerator cancels the two in the denominator, thus solving for \displaystyle x.

\displaystyle x=16

All Common Core: High School - Algebra Resources

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