Question

The sum of two numbers a and b is 20. Write an expression for the sum of their squares, in terms of a.

Answer 1

2a² - 40a + 400

Explanation:

a + b = 20

b = 20 - a

a² + b² = a² + (20 - a)²

a² + b² = a² + 20² - 40a + a²

a² + b² = 2a² - 40a + 400