Question

3. Given: a+b=12 and ab=9
Use (a + b)2 to find a² +bº. (Do not solve for a and b individually)

Answer 1

a²+b²=126

Explanation:

(a+b)²=a²+b²+2ab

(12)²=a²+b²+2×9

144=a²+b²+18

a²+b²=144-18=126