Advanced Math practice question

Answer: 6

s² = 4s + 12 gives s² − 4s − 12 = (s − 6)(s + 2) = 0, so s = 6.

Common wrong answers

If you answered 4

4 copies the coefficient.

If you answered 12

12 copies the constant.

If you answered -2

−2 is the other root, which cannot be a length.

More Advanced Math questions

• Medium
  What are the solutions to x² − 5x + 6 = 0?
• Medium
  The graph of f(x) = (x − 3)² + 4 is a parabola. What are the coordinates of its vertex?
• Medium
  If x² − 2x − 8 = (x + 2)(x − a), what is the value of a?
• Medium
  If √(x + 5) = 4, what is the value of x?
• Medium
  If f(x) = x + 3 and g(x) = 2x, what is f(g(4))?
• Medium
  What are the solutions to x² + 6x + 8 = 0?