First we want to isolate the x2-term. After that we can square root both sides of the equation.
The equation then has two real solutions: x=9 and x=-9.
Our x2-term stands alone on the left side, so in order to solve the equation we take the square root of both sides. But we cannot calculate the square root of -121. That is because there is no real number whose square is negative. Therefore, the equation has no real solutions.
After we have isolated the x2-term we can write the equation as x2=-1. Just like in Part B, this is an equation that lacks real solutions, because we must take the square root of a negative number to solve it.
Let's isolate the x2-term on one side. After that we can square root both sides.
This equation has two real solutions and they are x=-10 and x=10.