Question

6 times a number is 27 less than the square of that number. Find the positive solution.

Answer 1

Let x = your number.

6x = x^2 - 27. Subtract 6x from each side.

0 = x^2 - 6x - 27. Factor

0 = (x-9) (x+3). Set each term equal to zero

(x+3) = 0. Subtract 3 from each side.

x = -3. This is the negative solution.

(x-9) = 0. Add 9 to each side.

x = 9. This is the positive solution.