f(x)= 2/3x +4 output = 2

Question

Solve for y=f(x) for x

Find the input when the output is 2

Answer 1

2 = (2/3)x +4

1 =x/3 +2

x/3 = -1

x =-3

that's assuming by 2/3x you really meant (2/3)x. (but as written, you've got 2/(3x). If that's what you meant, then 2=2/3x +4 or

1= 1/3x +2

1/3x =-1

1 =-3x

x =-1/3. Strict adherence to PEMDAS order of operations would mean x=-1/3)

You most likely want x=-3 though