Algebra Questions

Multiple choice
  1. $1$ only
  2. $2$ only
  3. Both $1$ and $2$
  4. Neither $1$ not $2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The equation 4(x-p)(x-q) - r^2 = 0 can be written as 4x^2 - 4(p+q)x + 4pq - r^2 = 0. The discriminant D = [4(p+q)]^2 - 4(4)(4pq - r^2) = 16(p^2 + 2pq + q^2) - 16(4pq - r^2) = 16(p^2 - 2pq + q^2 + r^2) = 16[(p-q)^2 + r^2]. Since (p-q)^2 >= 0 and r^2 >= 0, D >= 0, so roots are real. If p=q and r=0, D=0, so roots are equal.

Multiple choice
  1. $a,b$ and $c$ are in AP
  2. $a,b$ and $c$ are in GP
  3. $a,b$ and $c$ are in HP
  4. $a,b$ and $c$ do not follow any regular pattern
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For equal roots, the discriminant D = b^2 - 4ac = 0. Here, [b(c-a)]^2 - 4[a(b-c)][c(a-b)] = 0. This simplifies to b^2(c-a)^2 - 4ac(ab - b^2 - ac + bc) = 0. This is a known condition for a, b, c in HP.