Simplify (3*) (x) - (x) (2x)

The answer is just x. you add 3x and x & you get 3x squared. and you do the other side & get 2x squared, when you subract them the squared cancels out & you subtract 3 & 2 and you're left with 1x aka x

(3x) (x) - (x) (2x)

3x^2 - 2x^2

= x^2