Answer:
x = 6
Step-by-step explanation:
Given ∠ 1 = ∠ 2 then the segment is an angle bisector and the ratios of sides to base are equal, that is
=
( cross- multiply )
x(x - 4) = 12 ← distribute left side
x² - 4x = 12 ( subtract 12 from both sides )
x² - 4x - 12 = 0 ← in standard form
(x - 6)(x + 2) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 6 = 0 ⇒ x = 6
x + 2 = 0 ⇒ x = - 2
However, x > 0 , thus x = 6