Question

If a-b= 3 and
`a^(2)-b^(2)`=33, find the value of a+b.

Answer 1

a=x b=y

`{x}^(2) - {y}^(2) = 33 \\ (x - y) * (x + y) = 33 \\ 3 * (x + y) = 33 \\ x + y = 33 / 3 \\ x + y = 11`
You only have to remember

`{x}^(2) - {y}^(2) = (x + y) * (x - y)`
since it's a rule