Answer:
∠ ABC = 64°
Step-by-step explanation:
The sum of the 3 angles in triangle ABC = 180°
sum the 3 angles, equate to 180 and solve for x
x² - 6x + 100 + x + 56 = 180 ( simplify left side )
x² - 5x + 156 = 180 ( subtract 180 from both sides )
x² - 5x - 24 = 0 ← quadratic equation in standard form
(x - 8)(x + 3) = 0 ← in factored form
equate each factor to zero and solve for x
x - 8 = 0 ⇒ x = 8
x + 3 = 0 ⇒ x = - 3
However, x > 0, then x = 8
Then
∠ ABC = x² = 8² = 64°