Answer:
x = 8
Explanation:
from the diagram
∠ CXD + ∠ DXE = ∠ CXE ( substitute values )
x² - 4 + 2x - 10 = 7x + 10
x² + 2x - 14 = 7x + 10 ( subtract 7x + 10 from both sides )
x² - 5x - 24 = 0 ← 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 + 5 = 0 ⇒ x = - 5
but x > 0 , then x = 8