Question

If a + b = 20 and ab = 75, find the value of a? + b2.​

Answer 1

a² + b² = 250

Explanation:

Given

a + b = 20 ( square both sides )

(a + b)² = 20² , that is

a² + b² + 2ab = 400 ( substitute ab = 75 )

a² + b² + 2(75) = 400

a² + b² + 150 = 400 ( subtract 150 from both sides )

a² + b² = 250