If a+b = 8 and ab = 15, what is the value of a2+b2?

If a+b = 8 and ab = 15, what is the value of a²+b²?

A 94

B 79

C 34

D 30

Solution

Correct Answer: Option C

a² + b² = (a + b )² - 2ab = (8)² - 2*15 = 64 - 30 = 34