The perimeter of a triangle is side a + side b + side c. so...
(2x + 4) + (2x + 4) + (2x + 4) = 6x + 12.
But if you need to go farther...
6x = -12
x = -2
then replace x in the original equation with -2......
2(-2) + 2(-2) + 2(-2)
multiply
(-4) + (-4) + (-4)
add
the answer should be -12
