Question

Considerando a função dada por f(x) = 1-2.x, calcule:

a) x, para que f(x) =-39

Answer 1

f(x) = 1-2x
-39=1-2x
-39-1=-2x
-40=-2x
-40*(-1)=-2x*(-1)
40=2x
x=40/2
x=20

Answer 2

f(X) = 1 - 2X --> -39 = 1-2X
2X = 1 + 39
2X = 40
X = 40/2
X = 20