Answer:
all three angles should add up to 180 so subtract what you know from 180 and you should be able to find everything from there
We want h(x) = g(x) - f(x).
h(x) = -2x + 9 -(6x - 5)
h(x) = -2x + 9 -6x + 5
h(x) = -8x + 14
DEC=72 degrees. The two angles equal each other so you much set them to equal each other.