Question

prove that the line joining the point of intersection of two angle bisector of the base angle of an isosceles triangle to the vertex bisect the Vertical angle​

Answer 1

a + b = 10, ab = 21

Cubing both sides,

(a + b)3 = (10)3

⇒ a3 + 63 + 3ab (a + b) = 1000

⇒  a3 + b3 + 3 x 21 x 10 = 1000

⇒  a3 + b3 + 630 = 1000

⇒  a3 + b3 = 1000 – 630 = 370

∴ a3 + b3 = 370