Question

Help with this difference quotient?

Let f(x)= 7-5x-2x^2

Use the difference quotient: f(x+h)-f(x)/h

I'm just not sure how to apply the f(x) in the f(x+h).

Answer 1

first replace x by ( x+h)
in f(x)

Answer 2

\[\huge\rm f(\color{Green}{x+h})=-2(\color{green}{x+h})^2 -5(\color{green}{x+h}) +7\]
like this

Answer 3

can you solve that ?? :-)

Answer 4

Oh okay so they would separated. That makes sense.

Answer 5

yeah replace x by x+h
and that's just f(x+h) part of the formula

Answer 6

((-2(x+h)^2)-(5x+h)+7)-(7-5x-2x^2)/h

Then I'll simplify

Answer 7

yep right :-)

Answer 8

((-2x-2h)^2)-(5x+5h)+7)-(7-5x-2x^2)/h

(-2x-2h)-(5x+5h)-(-5x-2x^2)/h

(2x^2-2x-7h)/h

Answer 9

\[\large\rm\frac{ (-2\color{red}{{(x+h})^2} -5(\color{green}{x+h}) +7 )-(7-5x-2x^2) }{ h }\] first sove parenthses
you can't distribute by 2 first
first step solve parenthses (x+h)^2foil

Answer 10

solve*

Answer 11

Oh pellet duh didn't see that, I should be writing it down then solving via computer aha

Answer 12

hmm parentheses first ! try again o^_^o

Answer 13

Okay, I don't know if what I got it right but 2(2x^2+2xh+h^2)-5h/h

Answer 14

okay (x+h)^2 = ??

Answer 15

(2x^2+2xh+h^2)

Answer 16

2x^2 ??

Answer 17

Whoops, I meant x^2