What is the answer 90=5x - (2x-30)

Before we begin, note that:

-ve * + ve = - ve

+ve * - ve = - ve

+ve * + ve = + ve

-ve * - ve = - ve

Now, the given is:

90 = 5x - (2x-30)

To solve for x, we will need to separate the x on one side of the equation and get its value as follows:

90 = 5x - (2x-30)

90 = 5x - 2x + 30

5x - 2x = 90 - 30

3x = 60

x = 60/3

x = 20