Find $f(a)$, $f(a + h)$, and the difference quotient, given $f(x)=7-8x+2x^2$
1,490
There is a small algebra mistake, notice $2(a+h)^2=2a^2+\color{red}4ah+2h^2$. From here your last line turns into $\frac{-8h+4ah+2h^2}{h}$, which simplifies to $-8+4a+2h$.
Related videos on Youtube
Author by
TheNewGuy
Updated on June 23, 2020Comments
-
TheNewGuy over 3 years
Question is here:
I need help with part c.
I tried plugging everything in and simplifying to a point where my final answer was $(-8h+2ah+2h^2)/h$
My work:
$(7-8a-8h+2(a+h)^2-7+8a-2a^2)/h$ combine like terms
$(-8h+2(a+h)^2 -2a)/h$ foil/expand
$(-8h+2a^2+2ah+2h^2-2a)/h$ combine like terms
$-8h+2ah+2h^2/h$
-
Mufasa over 8 yearsHINT: $h$ is a common factor of the numerator and the denominator and can therefore be cancelled out
-
Darrell over 8 yearsWhat is $2(a+h)^2$?
-
TheNewGuy over 8 yearsThanks everyone. I didn't realize I foiled it wrong because I did it quickly in my head.
-