Solve the quadratic equation.
x + 9x − 15 = 0
2
x =
9±√21
2
x =
9±√141
2
x =
−9±√141
2
x =
−9±√21
2
The correct solution is:
x = (-9 ± √141) / 2
x + 9x − 15 = 0
2
x =
9±√21
2
x =
9±√141
2
x =
−9±√141
2
x =
−9±√21
2
x = (-9 ± √141) / 2