Question

In ΔCDE, m∠C = (9x+11)^{\circ}(9x+11) ∘ , m∠D = (3x-15)^{\circ}(3x−15) ∘ , and m∠E = (2x+16)^{\circ}(2x+16) ∘ . What is the value of x?

Answer 1

x = 12

Explanation:

The sum of the 3 angles in a triangle = 180°

Sum the 3 given angles and equate to 180, that is

9x + 11 + 3x - 15 + 2x + 16 = 180, simplify left side

14x + 12 = 180 ( subtract 12 from both sides )

14x = 168 ( divide both sides by 14 )

x = 12