If a + b = 11 and ab = 15, then $a^2 + b^2 $ is equal to :
Answer & explanation
Correct answer: option 2
We know that,
a + b = 11 and ab = 15
(a + b)2 = a2 + b2 + 2ab
= 112 = a2 + b2 + 2 × 15
= a2 + b2 = 121 - 30
a2 + b2 = 91
If a + b = 11 and ab = 15, then $a^2 + b^2 $ is equal to :
Correct answer: option 2
We know that,
a + b = 11 and ab = 15
(a + b)2 = a2 + b2 + 2ab
= 112 = a2 + b2 + 2 × 15
= a2 + b2 = 121 - 30
a2 + b2 = 91