Question

If a squared plus b squared equals to 40 and ab equals 12 find a plus b and a minus b

Answer 1

Explanation:

`{a}^(2) + {b}^(2) = 40`

`ab = 12`

Notice that

`(a + b) {}^(2) = {a}^(2) + 2ab + {b}^(2)`

`(a - b) {}^(2) = {a}^(2) - 2ab + {b}^(2)`

So

`2ab = 24`

`- 2ab = 24`

So

`(a + b) {}^(2) = 64`

`a + b = 8`

Also,

`(a - b) {}^(2) = 16`

`a - b = 4`