How do i solve x2 - 10x = - 21?

X^2 - 10x = - 21 (adding both sides by 21)

x^2 - 10x + 21 = 0

Now, we can solve for x ... first thing that we have to do is, figure out what is the value of x that could cause the equation gives us 0 (zero as the result). The value is when x = 7 and x = - 3. Then we can simply right the equation as:

(x-7) (x+3) = 0 ... it means that:

x-7 = 0

x+3 = 0

So, the solution for x is ...

x = 7 and x = - 3