Multiple choice

If the roots of an equation $p{ x }^{ 2 }+qx+r=0$ are equal, then

  1. ${ q }^{ 2 }=pr$
  2. ${ q }^{ 2 }=4pr$
  3. ${ p }^{ 2 }=4qr$
  4. $p=qr$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For a quadratic equation ax^2 + bx + c = 0 to have equal roots, the discriminant D = b^2 - 4ac must be zero. Here, q^2 - 4pr = 0, so q^2 = 4pr.

AI explanation

For a quadratic equation to have equal roots, its discriminant must be equal to zero. The discriminant is calculated as q squared minus 4 times p times r. Setting this to zero gives q squared minus 4pr equals 0, which means q squared equals 4pr.

Keep practicing — related questions