Question

the beginning of the question is "if the slope of..." please help

Answer 1

we know that

If two lines are parallel, then their slopes are equal

In this problem

mAB=mCD

substitute the given values

3/4=(x-2)/12

solve for x

multiply by 12 both sides

(x-2)=12(3/4)

x-2=9

x=9=9+2

x=11