Question 40527
1) Solve for the variable:
{{{c(c-1)(c+13) = 0}}} Apply the zero products principle.
{{{c = 0}}} and/or {{{c-1 = 0}}} and/or {{{c+13 = 0}}}

Solutions are:
c = 0
c = 1
c = -13

2) Five times the square root of a number is 15, find the number:
Let n = the number.
{{{5sqrt(n) = 15}}} Divide both sides by 5.
{{{sqrt(n) = 3}}} Square both sides.
{{{n = 9}}}