Answer:
[tex]x=\frac{16}{5}[/tex]
Step-by-step explanation:
The given function is
[tex]f(x) = -5x +1+3[/tex]
Which can be rewritten also as
[tex]f(x) = -5x +4[/tex]
We want to find the values of x for which
[tex]f(x) = -12[/tex]
In order to do that, we just substitute -12 into f(x), and we solve the equation for x:
[tex]-12 = -5x + 4\\-16 = -5x\\x=\frac{-16}{-5}=\frac{16}{5}[/tex]