Question

How do you factor and solve `x^2=81`?

Answer 1

`x^2=81`
can be written as
`x^2 - 81 = 0`

by property , `color(blue)(a^2 - b^2 = (a+b)(a-b)`
The expression becomes
`x^2 - (9)^2= 0`

`color(blue)((x-9) (x+9))= 0`

equating each of the terms with zero we obtain the solution
`x-9 = 0`
and
`x+9 = 0`
the solutions are `color(blue)( x = 9 or x = -9`