Question

How do you solve `81x^2-10=-1`?

Answer 1

`x=+-1/3`

Explanation:

`"isolate "81x^2" by adding 10 to both sides"`

`81x^2=-1+10=9`

`"divide both sides by 81"`

`x^2=9/81=1/9`

`color(blue)"take the square root of both sides"`

`sqrt(x^2)=+-sqrt(1/9)larrcolor(blue)"note plus or minus"`

`x=+-1/3`

Answer 2

`x=pm1/3`

Explanation:

`81x^2=9`

`x^2=9/81`

`x=pmsqrt9/81`

`rArr pm3/9`

`rArr pm1/3`