PSAT Math : Algebra

Study concepts, example questions & explanations for PSAT Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #2791 : Sat Mathematics

If \small f(x) = 4x^{2}+3x+2 and \small g(x) = x+7, what is \small f(g(x))?

Possible Answers:

\small 4x^{2}+3x+72

\small 4x^{2}+3x+219

\small 4x^{2}+17x+72

\small 4x^{2}+59x+219

\small 4x^{2}+17x+219

Correct answer:

\small 4x^{2}+59x+219

Explanation:

\small 4(x+7)^{2} +3(x+7)+2

\small 4(x^{2} + 14x + 49)+ 3x +21 + 2

\small 4x^{2}+56x+196+3x+23

\small 4x^{2}+59x+219

Example Question #2792 : Sat Mathematics

If  and , which of the following could represent ?

Possible Answers:

Correct answer:

Explanation:

The number in the parentheses is what goes into the function.

For the function ,

 and

Example Question #2793 : Sat Mathematics

A function F is defined as follows:

for x2 > 1, F(x) = 4x2 + 2x – 2

for x2 < 1, F(x) = 4x2 – 2x + 2

What is the value of F(1/2)?

Possible Answers:

Correct answer:

Explanation:

For F(1/2), x2=1/4, which is less than 1, so we use the bottom equation to solve. This gives F(1/2)= 4(1/2)2 – 2(1/2) + 2 = 1 – 1 + 2 = 2

Example Question #11 : How To Find F(X)

Which of the statements describes the solution set for 7(x + 3) = 7x + 20 ? 

Possible Answers:

All real numbers are solutions.

There are no solutions.

x = 0

x = 1

Correct answer:

There are no solutions.

Explanation:

By distribution we obtain 7x – 21 = – 7x + 20. This equation is never possibly true.

Example Question #12 : How To Find F(X)

Will just joined a poetry writing group in town that meets once a week. The number of poems Will has written after a certain number of meetings can be represented by the function , where  represents the number of meetings Will has attended. Using this function, how many poems has Will written after 7 classes?

Possible Answers:

Correct answer:

Explanation:

For this function, simply plug 7 in for  and solve:

Example Question #51 : Algebraic Functions

If f(x)=x^{3} +\frac{4}{x} + \frac{x^{2}}{2} what is

Possible Answers:

Correct answer:

Explanation:

f(x)=x^{3} +\frac{4}{x} + \frac{x^{2}}{2}

f(4)=4^{3} +\frac{4}{4} + \frac{4^{2}}{2}

f(4)=64 + 1 + 8

f(4)=73

Example Question #982 : Psat Mathematics

If , find the value of .

Possible Answers:

Correct answer:

Explanation:

f(4) = 4 + 1/4 = 16/4 + 1/4 = 17/4

Example Question #983 : Psat Mathematics

If  and , what is ?

Possible Answers:

132

19

104

100

20

Correct answer:

132

Explanation:

g is a function of f, and f is a function of 3, so you must work inside out.

f(3) = 11

g(f(3)) = g(11) = 121 + 11 = 132

Example Question #984 : Psat Mathematics

Jamie buys a new fish tank. It is 45% full. She adds seven more liters of water, and it is 65% full. What is the capacity of Jamie's new fish tank?

Possible Answers:

22 liters

35 liters

27 liters

48 liters

None of the other answers are correct.

Correct answer:

35 liters

Explanation:

The algebraic expression for x, the capacity of the fishtank is:

0.45x+7=0.65x

0.45x+7-0.45x=0.65x-0.45x

0.2x=7

0.2x\times\frac{1}{0.2}=7\times\frac{1}{0.2}

x=35\hspace{1 mm}L

The capacity of the fishtank is 35 liters.

Example Question #985 : Psat Mathematics

 

 

 

 

Possible Answers:

Correct answer:

Explanation:

When we multiply a function by a constant, we multiply each value in the function by that constant. Thus, 2f(x) = 4x + 12. We then subtract g(x) from that function, making sure to distribute the negative sign throughout the function. Subtracting g(x) from 4x + 12 gives us 4x + 12 - (3x - 3) = 4x + 12 - 3x + 3 = x + 15. We then add 2 to x + 15, giving us our answer of x + 17.

Learning Tools by Varsity Tutors