SOLUTION: Given the function f(x)=4x^2-x+6, calculate f(x+5). I know how to do functions, but this one has me stumped. I tried doing it the regular way, and it was wrong, so here are the

Algebra ->  Functions -> SOLUTION: Given the function f(x)=4x^2-x+6, calculate f(x+5). I know how to do functions, but this one has me stumped. I tried doing it the regular way, and it was wrong, so here are the       Log On


   

Question 352269: Given the function f(x)=4x^2-x+6, calculate f(x+5).
I know how to do functions, but this one has me stumped. I tried doing it the regular way, and it was wrong, so here are the answer choices.
A)4x^2+4x+106
B)4x^2+9x+25
C)4x^2+39x+101
D)4x^2-39x-111
I really need help on this because if I do the problem, I can figure out the outside numbers, but I don't know how to get the middle number. Thanks in advance!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=4x%5E2-x%2B6 Start with the given function.


f%28x%2B5%29=4%28x%2B5%29%5E2-%28x%2B5%29%2B6 Replace each 'x' with 'x+5'


f%28x%2B5%29=4%28x%5E2%2B10x%2B25%29-%28x%2B5%29%2B6 FOIL


f%28x%2B5%29=4x%5E2%2B40x%2B100-x-5%2B6 Distribute.


f%28x%2B5%29=4x%5E2%2B39x%2B101 Combine like terms


So the answer choice is C)