Advanced Math practice question

Answer: 4

Square both sides: x² + 9 = 25 → x² = 16 → x = 4 (positive).

Common wrong answers

If you answered 2

2 comes from x² = 4, subtracting 9 from 13 rather than from 25.

If you answered 16

16 is x².

If you answered -4

−4 satisfies the equation but is not positive.

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?