Given then equation f(x)=-6x-2, determine f(4)

Evaluate f(-2) for the function f(x)= 4x squared-x+5

Given then equation f(x)=-6x-2, determine f(4)

Evaluate f(-2) for the function f(x)= 4x squared-x+5

Tutors, please sign in to answer this question.

Newark, DE

A function is a rule that you apply to a variable. In this case the variable,x, represents a number and the rules just tells you what to do with the number. For f(4), you do: 6*(4)-2 = 24-2 = 22, so f(4) = 22

Do you think you can do it for the other function? Remember to substitute the number given (-2) and apply the rule: 4x^2 -x +5

edit: that negative was hard to see: sorry, though if you follow the steps with the correct value the answer works out

Olney, MD

The notation f(4) means f(x=4). So just plug in 4 wherever there is an x:

f(x) = -6x - 2

f(4) = -6(4) - 2

f(4) = -24 - 2

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

f(-2) = 4(-2)^{2} - (-2) + 5

f(-2) = ?

Alex C.

Harvard/MIT Finance and Statistics Tutor

Fort Lee, NJ

5.0
(226 ratings)

Dana R.

English/Math SAT PrepTutor with PhD

Lynbrook, NY

4.8
(85 ratings)

Nafeesa M.

Expert SAT, ACT, Math, and French Tutor!

New York, NY

4.9
(115 ratings)

- Math 8622
- Algebra 2 3157
- Calculus 2023
- Trigonometry 1329
- Math Help 4863
- Algebra 1 3758
- Sequences 107
- Series 58
- Precalculus Homework 317
- Prealgebra 167