Multiple choice

The equation x2−12x+k= 0 has equal roots. Find k.

  1. 24

  2. 36

  3. 48

  4. 72
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For the equation x^2 - 12x + k = 0 to have equal roots, the discriminant b^2 - 4ac must be 0. Here, b = -12, a = 1, c = k. So, (-12)^2 - 4(1)(k) = 0, which means 144 - 4k = 0, so k = 36.

AI explanation

For a quadratic equation to have equal roots, its discriminant must equal zero, so b^2 - 4ac = 0. Substituting the values gives (-12)^2 - 4(1)(k) = 0, which simplifies to 144 - 4k = 0. Solving this yields k = 36.

Keep practicing — related questions