Question 372543
Let n = the number.
{{{n^2-15 = n+15}}} "...the square of a number (n) is decreased by 15, the result is equal to the number increased by 15."
Add 15 to both sides.
{{{n^2 = n+30}}} Subtract n from both sides.
{{{n^2-n = 30}}} Subtract 30 from both sides.
{{{n^2-n-30 = 0}}} Solve this quadratic equation by factoring.
{{{(n+5)(n-6) = 0}}}
{{{n = -5}}} or {{{n = 6}}}
As you can see, there are two answers:
-5 and 6