If px2 + qx + r = 0 has equal roots , then r = ……………A) q2/2p

1.	If px2 + qx + r = 0 has equal roots , then r = ……………A) q2/2pB) q/2pC) -q2/4pD) q2/4p
Answer» Correct option is (D) q²/4p Given that quadratic equation \(Px^2+qx+r=0\) has equal roots. Then its discriminant must be zero. i.e., D = 0 \(\Rightarrow(-q)^2-4\times p\times r=0\) \(\Rightarrow q^2-4pr=0\) \(\Rightarrow4pr=q^2\) \(\Rightarrow\) \(r=\frac{q^2}{4p}\) Correct option is D) q²/4p

If px2 + qx + r = 0 has equal roots , then r = ……………A) q2/2pB) q/2pC) -q2/4pD) q2/4p

Answer»

Correct option is (D) q²/4p

Given that quadratic equation \(Px^2+qx+r=0\) has equal roots.

Then its discriminant must be zero.

i.e., D = 0

\(\Rightarrow(-q)^2-4\times p\times r=0\)

\(\Rightarrow q^2-4pr=0\)

\(\Rightarrow4pr=q^2\)

\(\Rightarrow\) \(r=\frac{q^2}{4p}\)

Correct option is D) q²/4p