Question

if a² + b² = 15 and ab = 5 find a+b​

Answer 1

Correct option is

C

13

Formula

(a+b)

2

=a

2

+b

2

+2ab

=>a

2

+b

2

=(a+b)

2

−2ab

Given, a+b=5 and ab=6

So, a

2

+b

2

=(a+b)

2

−2ab=5

2

−2×6=25−12=13

Answer 2

Answer:

$\large\sf\blue{Answer:-}$

Formula

(a+b)

2

=a

2

+b

2

+2ab

=>a

2

+b

2

=(a+b)

2

−2ab

Given, a+b=5 and ab=6

So, a

2

+b

2

=(a+b)

2

−2ab=5

2

−2×6=25−12=13