Respuesta :
Since (2x-4)-(6x+6) is composed of the two phrases in parentheses which are added or subtracted, we can drop the parentheses, after distributing the (-).
So 2x-4-6x-6 = 2x-6x + -4-6
= -4x + -10 = -4x-10
So 2x-4-6x-6 = 2x-6x + -4-6
= -4x + -10 = -4x-10