## anonymous 5 years ago if f(x)=3x^2-2x-5, find(2u+1) can you explain how to work the problem and whats the answer i can get to f(2u+1)=3(2u+1) after that i don't know

$f(2u+1)=3(2u+1)^{2}-2(2u+1)-5$ Thats a start.

$=3(4u ^{2}+4u+1)-4u-2-5$ just keep on trucking!

Earth to shrryflores, do you follow so far?

4. anonymous

yes

Let's continue then: $12u ^{2}+12u+3-4u-7$ $12u ^{2}+8u+4$

change that +4 to -4

7. anonymous

ok it makes since

since there was no = sign I think that is as far as needed$12u ^{2}+12u-4$

$f(2u+1)=12u ^{2}+12u-4$

10. anonymous

$f(2u+1)=12u^2+8u-4$ You can find the roots of u using the quadratic formula: $u=-\frac{1}{3}\pm \frac{2}{3}\rightarrow u=-1, u=\frac{1}{3}$

I was wondering if it was to be taken any further? Couldn't determine if they were wanting the roots.

12. anonymous

I gave the roots just in case