Answer
The number is either -6 or 5.
Work Step by Step
Note, the 5 step process is as follows:
(1) Familiarize yourself with the problem.
(2) Translate the problem into Algebra.
(3) Solve.
(4) Check. Note, if we want to check a solution, we would plug it back into the equation and check that the equation yields a true statement.
(5) State the answer.
After becoming familiar with the problem, we find:
$$x=x^2-30 \\ x_{1,\:2}=\frac{-\left(-1\right)\pm \sqrt{\left(-1\right)^2-4\cdot \:1\left(-30\right)}}{2\cdot \:1} \\ x=6,\:x=-5$$
The number is either -6 or 5.
