Answer:
<A = 76°
<B = 63°
<C = 41°
Plug in the value of x
<C = 34 + 7
<C = 41°
Explanation:
(sum of ∆)
Solve for x

Add like terms

Subtract 78 from each side


Divide both sides by 3
x = 34
<A = 2x + 8
Plug in the value of x
<A = 2(34) + 8 = 76°
<B = 63°
<C = x + 7
Plug in the value of x
<C = 34 + 7
<C = 41°