Question

f(x+1)=x^2+2x

Answer 1

\[f(x+1)=x^2+2x\]
find \[f(x)\]

Answer 2

f(x+1) = x^2+2x
= (x+1-1)^2 + 2(x+1-1)

Answer 3

so is it possible tofind f(x)

Answer 4

oh\[f(x)=(x-1)^2+2(x-1)\]

Answer 5

is it right

Answer 6

looks right to me

Answer 7

you may simplify and say, f(x) = x^2-1

Answer 8

what about\[g(x^2+1)=x^2+2x\]

Answer 9

\[x^2+1-1+2(x^2+1)-2x^2-2+2x\]

Answer 10

\[g(x)=x-1+2x-2x^2-2+2x\]

Answer 11

doesnt look correct

Answer 12

whats wrong

Answer 13

work it in reverse and see if u get g(x^2+1) back

Answer 14

the square is not crrect

Answer 15

check if this works :
g(x) = x-1 + 2sqrt(x-1)

Answer 16

it works so

Answer 17

if i let \[x^2+1=k\]
\[x=\sqrt{k-1}\]
\[g(x^2+1)=x^2+2x\]
\[g(k)=k-1+2\sqrt{k-1}\]

Answer 18

wonderful ! that looks very good method :)

Answer 19

wowijust made this up its not serious

Answer 20

imean this questions

Answer 21

i see, i was just eyeballing before for the function... but this method of urs is very good, thnks for sharing :)

Answer 22

thanks its good tohave people who can help thanks for sharing your thoughs