SSAT Upper Level Math : Algebra

Study concepts, example questions & explanations for SSAT Upper Level Math

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Example Questions

Example Question #181 : Ssat Upper Level Quantitative (Math)

\displaystyle x> 0 and \displaystyle y > 0

\displaystyle x^{2} = 8

\displaystyle y^{2} = 18

Evaluate \displaystyle (x+ y) ^{2}.

Possible Answers:

\displaystyle 26

\displaystyle 144

\displaystyle 38

\displaystyle 50

Correct answer:

\displaystyle 50

Explanation:

By the perfect square trinomial pattern,

\displaystyle (x+ y) ^{2}

\displaystyle =x^{2} +2xy+ y ^{2}

\displaystyle x^{2} = 8 and \displaystyle y^{2} = 18.

Also, by the Power of a Power Principle, 

\displaystyle (xy) ^{2} = x^{2} y^{2} = 8 \cdot 18 = 144

so, since \displaystyle x and \displaystyle y are both positive, 

\displaystyle xy = \sqrt{(xy) ^{2} }= \sqrt{144}= 12.

Therefore, 

\displaystyle (x+ y) ^{2}

\displaystyle =x^{2} +2xy+ y ^{2}

\displaystyle = 8 +2 (12)+18

\displaystyle = 8 +24 +18

\displaystyle = 50

 

Example Question #181 : Algebra

\displaystyle y^{3} = -17

\displaystyle y^{9} = ?

Possible Answers:

\displaystyle 51

\displaystyle -4,913

\displaystyle -51

\displaystyle 4,913

Correct answer:

\displaystyle -4,913

Explanation:

By the Power of a Power Principle, 

\displaystyle (y ^{3} ) ^{3} = y ^{3 \cdot 3} = y ^{9}

Therefore, we substitute, keeping in mind that an odd power of a negative number is also negative:

\displaystyle y ^{9} = (y ^{3} ) ^{3}

\displaystyle = (-17) ^{3}

\displaystyle = - 17 ^{3}

\displaystyle = - (17 \cdot 17\cdot 17)

\displaystyle = -4,913

Example Question #183 : Ssat Upper Level Quantitative (Math)

\displaystyle x> 0 and \displaystyle y > 0

\displaystyle x^{2} = 18

\displaystyle y^{2} = 8

Evaluate \displaystyle (x- y) ^{2}.

Possible Answers:

\displaystyle 10

\displaystyle 50

\displaystyle 2

\displaystyle 26

Correct answer:

\displaystyle 2

Explanation:

By the perfect square trinomial pattern,

\displaystyle (x- y) ^{2}

\displaystyle =x^{2} -2xy+ y ^{2}

\displaystyle x^{2} =1 8 and \displaystyle y^{2} = 8.

Also, by the Power of a Power Principle, 

\displaystyle (xy) ^{2} = x^{2} y^{2} = 18 \cdot 8 = 144

so, since \displaystyle x and \displaystyle y are both positive,

\displaystyle xy = \sqrt{(xy) ^{2} }= \sqrt{144}= 12.

Therefore, 

\displaystyle (x- y) ^{2}

\displaystyle =x^{2} -2xy+ y ^{2}

And, substituting:

\displaystyle x^{2} -2xy+ y ^{2}

\displaystyle =18 -2 (12)+8

\displaystyle =18 -24 +8

\displaystyle = 2

Example Question #184 : Ssat Upper Level Quantitative (Math)

\displaystyle t^{6} = 144

\displaystyle x^{6}= 81

\displaystyle t > 0, x< 0

Evaluate the expression \displaystyle (t-x) (t^{2}+tx+x^{2}).

Possible Answers:

\displaystyle 21

\displaystyle -21

\displaystyle 3

\displaystyle -3

Correct answer:

\displaystyle 21

Explanation:

Multiply out the expression by using multiple distributions and collecting like terms:

\displaystyle (t-x) (t^{2}+tx+x^{2})

\displaystyle = t (t^{2}+tx+x^{2}) - x (t^{2}+tx+x^{2})

\displaystyle = t \cdot t^{2}+ t \cdot tx+ t \cdot x^{2} - x \cdot t^{2}- x \cdot tx- x \cdot x^{2}

\displaystyle = t^{3}+ t^{2} x+ t x^{2} - t^{2} x- tx^{2} - x^{3}

\displaystyle = t^{3}+ t^{2} x- t^{2} x + t x^{2} - tx^{2} - x^{3}

\displaystyle = t^{3} - x^{3}

Since \displaystyle (t^{3} ) ^{2} = t ^{3 \cdot 2 } = t^{6} by the Power of a Power Principle,

\displaystyle t^{3} = \pm \sqrt{ t^{6}} = \pm \sqrt{144} = \pm 12.

However, \displaystyle t is positive, so \displaystyle t^{3} is as well, so we choose \displaystyle t^{3} = 12.

Similarly, 

\displaystyle x^{3} = \pm \sqrt{x^{6}} = \pm \sqrt{81} = \pm 9.

However, since \displaystyle x is negative, as an odd power of a negative number, \displaystyle x^{3} is as well, so we choose \displaystyle x^{3} = -9.

Therefore, substituting:

\displaystyle (t-x) (t^{2}+tx+x^{2}) = t^{3} - x^{3} = 12 - (-9) = 21 

Example Question #121 : How To Find The Properties Of An Exponent

\displaystyle A and \displaystyle B are both positive integers; A is odd. What can you say about the number 

\displaystyle (A + B + 1)^{A+B+1} ?

Possible Answers:

\displaystyle (A + B + 1)^{A+B+1} is even if \displaystyle B is even, and can be odd or even if \displaystyle B is odd.

\displaystyle (A + B + 1)^{A+B+1} is even if \displaystyle B is odd, and can be odd or even if \displaystyle B is even.

\displaystyle (A + B + 1)^{A+B+1} is odd if \displaystyle B is odd, and can be odd or even if \displaystyle B is even.

\displaystyle (A + B + 1)^{A+B+1} is even if \displaystyle B is odd, and odd if \displaystyle B is even.

\displaystyle (A + B + 1)^{A+B+1} is odd if \displaystyle B is odd, and even if \displaystyle B is even.

Correct answer:

\displaystyle (A + B + 1)^{A+B+1} is odd if \displaystyle B is odd, and even if \displaystyle B is even.

Explanation:

If \displaystyle B is odd, then \displaystyle A + B +1, the sum of three odd integers, is odd; an odd number taken to any positive integer power is odd.

If \displaystyle B is even, then \displaystyle A + B +1, the sum of two odd integers and an even integer, is even; an even number taken to any positive integer power is even. 

Therefore, \displaystyle (A + B + 1)^{A+B+1} always assumes the same odd/even parity as \displaystyle B.

Example Question #181 : Algebra

Give the equation of a line that passes through the point \displaystyle (4,7) and has slope 1.

Possible Answers:

\displaystyle x-y = -3

\displaystyle x = 4

\displaystyle x-y = 3

\displaystyle y = 7

\displaystyle x + y = 11

Correct answer:

\displaystyle x-y = -3

Explanation:

We can use the point slope form of a line, substituting \displaystyle m = 1, x_{1} = 4, y _{1} = 7.

\displaystyle y- y_{1} = m (x-x_{1})

\displaystyle y- 7 = 1 (x-4)

\displaystyle y- 7 = x-4

\displaystyle y- 7 -y +4 = x-4 -y +4

\displaystyle -3 = x-y

or 

\displaystyle x-y = -3

Example Question #182 : Algebra

A line can be represented by \displaystyle 2x+3y=6. What is the slope of the line that is perpendicular to it?

Possible Answers:

\displaystyle \frac{2}{3}

\displaystyle \frac{3}{2}

\displaystyle -\frac{2}{3}

\displaystyle \frac{3}{4}

\displaystyle 2

Correct answer:

\displaystyle \frac{3}{2}

Explanation:

You will first solve for Y, to get the equation in \displaystyle y=mx+b form.

\displaystyle m represents the slope of the line, which would be \displaystyle -\frac{2}{3}.

A perpendicular line's slope would be the negative reciprocal of that value, which is \displaystyle \frac{3}{2}.

Example Question #182 : Algebra

Find the equation the line goes through the points \displaystyle (3,4) and \displaystyle (0,2).

Possible Answers:

\displaystyle y=-\frac{2}{3}x+2

\displaystyle y=-\frac{3}{2}x+2

\displaystyle y=\frac{2}{3}x+2

\displaystyle y=\frac{3}{2}x+2

Correct answer:

\displaystyle y=\frac{2}{3}x+2

Explanation:

First, find the slope of the line.

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}=\frac{2-4}{0-3}=\frac{-2}{-3}=\frac{2}{3}

Now, because the problem tells us that the line goes through \displaystyle (0,2), our y-intercept must be \displaystyle 2.

Putting the pieces together, we get the following equation:

\displaystyle y=\frac{2}{3}x+2

Example Question #2 : How To Find The Equation Of A Line

A line passes through the points \displaystyle (-4, 6) and \displaystyle (-2, -2). Find the equation of this line.

Possible Answers:

\displaystyle y=4x+10

\displaystyle y=-\frac{1}{4}x+10

\displaystyle y=\frac{1}{4}x-8

\displaystyle y=-4x-10

Correct answer:

\displaystyle y=-4x-10

Explanation:

To find the equation of a line, we need to first find the slope.

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}=\frac{-2-6}{-2-(-4)}=\frac{-8}{2}=-4

Now, our equation for the line looks like the following:

\displaystyle y=-4x+b

To find the y-intercept, plug in one of the given points and solve for \displaystyle b. Using \displaystyle (-4, 6), we get the following equation:

\displaystyle 6=-4(-4)+b

Solve for \displaystyle b.

\displaystyle 6=16+b

\displaystyle b=-10

Now, plug the value for \displaystyle b into the equation.

\displaystyle y=-4x-10

Example Question #2 : How To Find The Equation Of A Line

What is the equation of a line that passes through the points \displaystyle (8,1) and \displaystyle (-2, -7)?

Possible Answers:

\displaystyle y=\frac{27}{5}x-\frac{4}{5}

\displaystyle y=\frac{4}{5}x-\frac{27}{5}

\displaystyle y=-\frac{4}{5}x+\frac{27}{5}

\displaystyle y=\frac{5}{4}x+\frac{32}{5}

Correct answer:

\displaystyle y=\frac{4}{5}x-\frac{27}{5}

Explanation:

First, we need to find the slope of the line.

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}=\frac{-7-1}{-2-8}=\frac{-8}{-10}=\frac{4}{5}

Next, find the \displaystyle y-intercept. To find the \displaystyle y-intercept, plug in the values of one point into the equation \displaystyle y=mx+b, where \displaystyle m is the slope that we just found and \displaystyle b is the \displaystyle y-intercept.

\displaystyle 1=8(\frac{4}{5})+b

Solve for \displaystyle b.

\displaystyle 1=\frac{32}{5}+b

\displaystyle b=-\frac{27}{5}

Now, put the slope and \displaystyle y-intercept together to get \displaystyle y=\frac{4}{5}x-\frac{27}{5}

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