SAT Math : Algebra

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #571 : Algebra

Factor 2x2 - 5x – 12

Possible Answers:

(x + 4) (2x + 3)

(x + 4) (2x + 3)

(x - 4) (2x + 3)

(x – 4) (2x – 3)

Correct answer:

(x - 4) (2x + 3)

Explanation:

Via the FOIL method, we can attest that x(2x) + x(3) + –4(2x) + –4(3) = 2x2 – 5x – 12.

Example Question #1 : How To Use Foil

x > 0.

Quantity A: (x+3)(x-5)(x)

Quantity B: (x-3)(x-1)(x+3)

Possible Answers:

The two quantities are equal

Quantity B is greater

Quantity A is greater

The relationship cannot be determined from the information given

Correct answer:

Quantity B is greater

Explanation:

 

Use FOIL: 

 

  (x+3)(x-5)(x) = (x2 - 5x + 3x - 15)(x) = x3 - 5x2 + 3x2 - 15x = x3 - 2x2 - 15x for A.

 

  (x-3)(x-1)(x+3) = (x-3)(x+3)(x-1) = (x2 + 3x - 3x - 9)(x-1) = (x2 - 9)(x-1)

  (x2 - 9)(x-1) = x3 - x2 - 9x + 9 for B. 

The difference between A and B: 

 (x3 - 2x2 - 15x) - (x3 - x2 - 9x + 9) = x3 - 2x2 - 15x - x3 + x2 + 9x - 9

 = - x2 - 4x - 9. Since all of the terms are negative and x > 0:

  A - B < 0.

Rearrange A - B < 0:

  A < B

 

 

 

Example Question #572 : Algebra

Solve for all real values of .

Possible Answers:

Correct answer:

Explanation:

First, move all terms to one side of the equation to set them equal to zero.

All terms contain an , so we can factor it out of the equation.

Now, we can factor the quadratic in parenthesis. We need two numbers that add to and multiply to .

We now have three terms that multiply to equal zero. One of these terms must equal zero in order for the product to be zero.

Our answer will be .

Example Question #188 : New Sat

Find the product in terms of :

Possible Answers:

Correct answer:

Explanation:

This question can be solved using the FOIL method. So the first terms are multiplied together:

This gives:

The x-squared is due to the x times x. 

The outer terms are then multipled together and added to the value above. 

The inner two terms are multipled together to give the next term of the expression.

Finally the last terms are multiplied together.

All of the above terms are added together to give:

Combining like terms gives

.

Example Question #4 : How To Use Foil

Expand the following expression:

Possible Answers:

Correct answer:

Explanation:

Expand the following expression:

Let's begin by recalling the meaning of FOIL: First, Outer, Inner, Last.

This means that in a situation such as we are given here, we need to multiply all the terms in a particular way. FOIL makes it easy to remember to multiply each pair of terms.

Let's begin:

First: 

Outer:

Inner:

Last:

Now, put it together in standard form to get:

Example Question #114 : Exponents

If  and are positive integers and , then what is the value of ?

Possible Answers:

Correct answer:

Explanation:

43 = 64

Alternatively written, this is 4(4)(4) = 64 or 43 = 641.

Thus, m = 3 and n = 1.

m/n = 3/1 = 3.

Example Question #115 : Exponents

Write the following logarithm in expanded form:

 

Possible Answers:

Correct answer:

Explanation:

Example Question #2353 : Sat Mathematics

If  and  are both rational numbers and , what is ?

Possible Answers:

Correct answer:

Explanation:

This question is asking you for the ratio of m to n.  To figure it out, the easiest way is to figure out when 4 to an exponent equals 8 to an exponent.  The easiest way to do that is to list the first few results of 4 to an exponent and 8 to an exponent and check to see if any match up, before resorting to more drastic means of finding a formula.

And, would you look at that. .  Therefore, .

Example Question #2353 : Sat Mathematics

Simplify: 

Possible Answers:

Correct answer:

Explanation:

If you don't already have the pattern memorized, use FOIL. It's best to write out the parentheses twice (as below) to avoid mistakes:

Example Question #573 : Algebra

Simplify the radical.

\sqrt{3283}

Possible Answers:

56

7\sqrt{63}

57.3

7\sqrt{67}

67\sqrt{49}

Correct answer:

7\sqrt{67}

Explanation:

We can break the square root down into 2 roots of 67 and 49. 49 is a perfect square and reduces to 7.

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