the square of a number added to 25 equals 10

Question

The square of a number added to 25 equals 10 times the number. What is the number?

Let x = the number.  The statement, "The square of a number added to 25 equals 10 times the number," translates to the equation x² + 25 = 10x. Put the equation in standard form ax² + bx + c       0, and set it equal to zero: x² - 10x + 25 = 0. Factor the left side of the equation: (x - 5)(x - 5) = 0. Set each factor equal to zero and solve: x - 5 = 0 or x - 5 = 0; x = 5 or x = 5. The number is 5.