Question

f^-1(4) when f(x) = 3x minus 4, all over 5
will give medals, please help me solve this

Answer 1

f^(-1)(x) is the inverse of f(x). To find the inverse:
1. Replace f(x) with y
2. Swap the places of x and y
3. Solve for y again
4. Replace y with f^(-1)(x)
5. Plug in your x value

Answer 2

y= 3x - 4 over 5
x= 3y - 4 over 5
4= 3y - 4 over 5
am I right so far @iPwnBunnies

Answer 3

That's another way to do it lol. I said solve for y before you plug in the x-value to distinguish f(x) from f^(-1).

Answer 4

Then times five by four and add 4 so 24= 3y then divide by 3 and I get 8?

Answer 5

Oh I'm sorry I get a bit confused

Answer 6

It is 8 though, when I do it quick in my head.

Answer 7

x = (3y-4)/5
y = (5x+4)/3
So, f^(-1)(x) = (5x+4)/3

Those were the extra steps to distinguish the two functions lol.

Answer 8

Ok thank you so much! (: