Question

PLEASE HELP!!!!!!! Let f(x) = 5x2 + 5x − 4. Find and simplify the following. f (4/a)

Answer 1

\[f(\frac{ 4 }{ a }) = 5(\frac{ 4 }{ a })^{2}+5(\frac{ 4 }{ a })-4\]

Answer 2

Can you solve it from that?

Answer 3

no thats where im stuck

Answer 4

Okay, be sure to square both the 4 and the a in the first term

Answer 5

so you would end up with 5(16/a^2) +20/a - 4

Answer 6

okay then what?

Answer 7

Then you need to combine into a fraction by multiplying the fractions by the LCD
so you'd have 5 x (16+20a)/(a^2)

Answer 8

then you still have the -4 to deal with; so in the end you'll have 5 x (16+20a-4a^2)/a^2

Answer 9

then simplify from there, let me know what you get

Answer 10

80+100a-20a^2 / a^2

Answer 11

are there any terms you can cancel?

Answer 12

a^2 ?

Answer 13

so would it be 80+100a-20 ?

Answer 14

hello?

Answer 15

yes, one sec

Answer 16

ok so the final answer is 100a+60?

Answer 17

I'd leave it as the fraction: (-4a^2 + 20a +80)/a^2

Answer 18

ok thanks