Multiple choice

If one root of the equation $x^2-\lambda x+12=0$ is even prime while $x^2 +\lambda x+\mu =0$ has equal roots, then $\mu$ is equal to

  1. $8$
  2. $16$
  3. $24$
  4. $32$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The even prime root is 2. Substituting x=2 into x^2 - lambda*x + 12 = 0 gives 4 - 2*lambda + 12 = 0, so lambda = 8. For x^2 + 8x + mu = 0 to have equal roots, the discriminant must be 0: 8^2 - 4*mu = 0, so 64 = 4*mu, mu = 16.

AI explanation

The only even prime number is 2, so substituting x=2 into the first equation x^2 - lx + 12 = 0 gives 4 - 2l + 12 = 0. Solving for l yields 2l = 16, so l = 8. The second equation x^2 + lx + u = 0 has equal roots, meaning its discriminant must be zero: l^2 - 4u = 0. Substituting l = 8 gives 64 - 4u = 0, which results in u = 16.