Question

Solve the equation for all values of x by completing the square. x²+20x=-87

Answer 1

For this case we can do the following:

`x^2+20x+((20)/(2))^2=-87+((20)/(2))^2`

Then when we simplify we got:

`x^2+20x+100=-87+100`

If we simplify we got:

`(x+10)^2=13`

Taking square root we got:

`x+10=\pm\sqrt[]{13}`

Then the two solutions are:

`x_1=-\sqrt[]{13}-10,x_2=\sqrt[]{13}-10`