Question

A.a + b.b = 612
And
a+b = 30

so a.b?
Pls help.

Answer 1

ab = 144

Explanation:

Assuming you mean a² + b² = 612, then

(a + b)² = a² + 2ab + b² , that is

30² = a² + 2ab + b² , so

a² + 2ab + b² = 900

a² + b² + 2ab = 900 ← substitute a² + b² = 612

612 + 2ab = 900 ( subtract 612 from both sides )

2ab = 288 ( divide both sides by 2 )

ab = 144