Advanced Math practice question

Answer: 36

(x − 3)(x + 3) = x² − 9, so x² − 9 = 27 and x² = 36.

Common wrong answers

If you answered 6

6 is a value of x, but the question asks for x².

If you answered 18

18 comes from x² − 9 = 27 solved as x² = 27 − 9.

If you answered 30

30 comes from x² − 3 = 27, using 3 instead of 9.

More Advanced Math questions

• Easy–Medium
  If f(x) = 2x² − 3, what is f(4)?
• Easy–Medium
  Which expression is equivalent to (2x³)(3x⁴)?
• Easy–Medium
  What are the solutions to x² − 16 = 0?
• Easy–Medium
  Which expression is equivalent to (x + 5)²?
• Easy–Medium
  For x ≠ 0, which expression is equivalent to (x² + 3x) / x?
• Easy–Medium
  What are the solutions to the equation 2(x − 3)² − 32 = 0 ?