Can someone do this for me ? i have maths first lesson tomorrow i need !

Explanation:

We're told that f(x) = -4. That means we can replace the f(x) in the first equation and solve for x.

f(x) = -5x+1

-4 = -5x+1 replaced f(x) with -4

-5x+1 = -4

-5x = -4-1

-5x = -5

x = -5/(-5)

x = 1

As a way to check, we plug in x = 1 to get...

f(x) = -5x+1

f(1) = -5(1)+1

f(1) = -5+1

f(1) = -4

So the answer is confirmed. If f(x) = -4, then x = 1.