Answer:
The second one (3x, 9x)
Step-by-step explanation:
Like terms are the terms that either have the same variable or have no variable.
The area of a triangle is A= 1/2bh. Plugging in the values you know, 30= 1/2*12*h.
Solving for h,
30= 1/2*12*h
30= 6h
h=5
The height of the triangle is 5 units.
