PSAT Math : Variables

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #21 : Variables

Which of the following monomials has degree 999?

Possible Answers:

None of the other responses is correct.

Correct answer:

Explanation:

The degree of a monomial term is the sum of the exponents of its variables, with the default being 1.

For each monomial, this sum - and the degree - is as follows:

 

 (note - 999 is the coefficient)

 

 is the correct choice.

Example Question #22 : Variables

Find the degree of the polynomial

Possible Answers:

None of the other answers

Correct answer:

Explanation:

The degree of the polynomial is the largest degree of any one of it's individual terms.

The degree of  is 

The degree of   is 

The degree of  is 

The degree of  is 

The degree of   is 

 is the largest degree of any one of the terms of the polynomial, and so the degree of the polynomial is .

Example Question #1 : Polynomials

Add the polynomials.

Possible Answers:

Correct answer:

Explanation:

We can add together each of the terms of the polynomial which have the same degree for our variable. 

Example Question #21 : Variables

Possible Answers:

Correct answer:

Explanation:

Step 1: Distribute the negative to the second polynomial:

Step 2: Combine like terms:

Example Question #2 : Polynomials

F(x) = x^{3} + x^{2} - x + 2 

and

G(x) = x^{2} + 5  

What is ?

Possible Answers:

(FG)(x) = x^{3} - x - 3

(FG)(x) = x^{5} + x^{4} - x^{3} + 2x^{2} - 5x -10

(FG)(x) = x^{5} + x^{4} - x - 2

(FG)(x) = x^{3} + 2x^{2} - x + 7

(FG)(x) = x^{5} + x^{4} +4x^{3} + 7x^{2} - 5x +10

Correct answer:

(FG)(x) = x^{5} + x^{4} +4x^{3} + 7x^{2} - 5x +10

Explanation:

(FG)(x) = F(x)G(x) so we multiply the two function to get the answer.  We use x^{m}x^{n} = x^{m+n}

Example Question #1 : Multiplying And Dividing Polynomials

Multiply:

Possible Answers:

Correct answer:

Explanation:

This product fits the sum of cubes pattern, where :

So

Example Question #1 : Polynomials

If 3 less than 15 is equal to 2x, then 24/x must be greater than

 

Possible Answers:

5

6

4

3

Correct answer:

3

Explanation:

Set up an equation for the sentence: 15 – 3 = 2x and solve for x.  X equals 6. If you plug in 6 for x in the expression 24/x, you get 24/6 = 4. 4 is only choice greater than a. 

 

 

Example Question #2 : Polynomials

Given a♦b = (a+b)/(a-b) and b♦a = (b+a)/(b-a), which of the following statement(s) is(are) true:

I. a♦b = -(b♦a)

II. (a♦b)(b♦a) = (a♦b)2

III. a♦b + b♦a = 0

Possible Answers:

I only

I and III

I, II and III

I and II

II & III

Correct answer:

I and III

Explanation:

Notice that - (a-b) = b-a, so statement I & III are true after substituting the expression. Substitute the expression for statement II gives ((a+b)/(a-b))((a+b)/(b-a))=((a+b)(b+a))/((-1)(a-b)(a-b))=-1 〖(a+b)〗2/〖(a-b)〗2 =-((a+b)/(a-b))2 = -(a♦b)2 ≠ (a♦b)2

Example Question #11 : Polynomial Operations

If a positive integer a is divided by 7, the remainder is 4.  What is the remainder if 3a + 5 is divided by 3?

Possible Answers:

3

2

4

5

6

Correct answer:

2

Explanation:

The best way to solve this problem is to plug in an appropriate value for a.  For example, plug-in 11 for because 11 divided by 7 will give us a remainder of 4. 

Then 3a + 5, where = 11, gives us 38.  Then 38 divided by 3 gives a remainder of 2.

 

The algebra method is as follows:

a divided by 7 gives us some positive integer b, with a remainder of 4.

Thus,

/ 7 = b  4/7

/ 7 = (7b + 4) / 7

a = (7b + 4)

 

then 3a + 5 = 3 (7+ 4) + 5

(3a+5)/3 = [3(7+ 4) + 5] / 3

= (7+ 4) + 5/3

The first half of this expression (7b + 4) is a positive integer, but the second half of this expression (5/3) gives us a remainder of 2.

Example Question #1 : How To Divide Polynomials

 

 

Polydivision1

Possible Answers:

45

42

36

100

38

Correct answer:

42

Explanation:

Polydivision2

 

 Polydivision4

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