Question

f(x) = x+1/x+7
Find f^-1(-5)

Answer 1

y = x+1/x+7
x/1 = y+1/y-3
x(y-3)=y+1
xy-3x=y+1
xy-y-3x=1
xy-y=3x+1
y(x-1)=3x+1
f^-1(x) = 3x+1/x-1
f^-1(5) = 3(-5)+1/-5-1=-15+1/-6=-16/-6=8/3

Answer 2

I didn't get the correct answer

Answer 3

@jim_thompson5910 @ganeshie8 @mathslover @jigglypuff314 @zzr0ck3r

Answer 4

y = x+1/x+7
x/1 = y+1/y-3
you changed the 7 to a 3?

Answer 5

oh I didn't see that!

Answer 6

that will change my answer

Answer 7

I'm still trying so what I got was 17/3

Answer 8

x(y+7)=y+1
xy + 7x = y + 1
y - xy = 7x - 1
y (1-x) = 7x-1
y = (7x-1)/(1-x)

Answer 9

where did the +1 change to a -1?

Answer 10

@jigglypuff314

Answer 11

you subtracted xy and -1 from both sides

Answer 12

OK, I see what you did :)