Solve x2 + 10x = -21.
x = 7 and x = 3
x = -7 and x = -3
x = -7 and x = 3
x = 7 and x = -3
x = 7 and x = 3
x = -7 and x = -3
x = -7 and x = 3
x = 7 and x = -3