SAT MAth Question — Find x if k = 3

In this problem, we are asked to find the value of x when k = 3

We have to substitute k =3 in the equation (x-1)/3 = k

The equation becomes (x-1)/3 = 3

The goal is to isolate x. We can do so by getting rid of the “3” on both the left side of the equal sign. This would require us to multiply both sides of the equation by 3. 3 will cancel out on the left-hand side and we multiply the 3 on the right-hand side:

x-1 = 9

To isolate for x, we simply need to add a “1” on both sides of the equality sign.

x — 1 + 1 = 9 + 1

This simplifies to

x = 9 + 1 = 10

The answer simplifies to d)

Below is the same procedure step-by-step color-coded

We can double-check that x = 10 (option d) the following way