Question

How do you solve `8-8a^2=-792`?

Answer 1

`a = +-10`

Explanation:

`8-8a^2= -792`

`8a^2 = 800`

`a^2 = 100`

`a = +-sqrt100`

`a = +-10`

Answer 2

`a=±10`

Explanation:

What we want to do here is isolate the `-8a^2` term on the left side of the equation while having the numeric value on the right.

To do this subtract 8 from both sides.

`cancel(8)cancel(-8)-8a^2=-792-8`

`rArr-8a^2=-800`

now divide both sides by -8

`(cancel(-8)^1 a^2)/cancel(-8)=(cancel(-800)^(100))/cancel(-8)^1rArra^2=100`

now take the 'square root' of both sides

`sqrt(a^2)=±sqrt100rArra=±10`