Question

find ab when
a+b=7 and a²+b²=11​

Answer 1

Given, a+b=7 and a²+b²=11

We have: a²+b² = (a+b)²-2ab

or, 11 = 7²- 2ab

or, 11 = 49 -2ab

or, 11+2ab = 49

or, 2ab = 49-11

or, 2ab = 38

or, ab = 38/2

= 19 Ans.

Answer 2

Answer:

we know that:

(a+b)²=a²+b²+2ab

7²=11+2ab

49=11+2ab

2ab=49-11

2ab=38

ab=38\2

ab=19