Respuesta :

Answer:

It's 5

Step-by-step explanation:

-4x+5=-15 (subtract 5)

-4x=-20 (divide by -4)

x=5

Step-by-step explanation:

Work backwards. First, create a function:

f(x) = x

First, instead of adding 5, subtract it:

f(x) = x - 5

Then, divide by -4:

f(x) = (x - 5) ÷ -4

Then plug in -15:

f(-15) = (-15 - 5) ÷ 4

= -20 ÷ -4

= 20 ÷ 4

= 5