Question

The quadratic expression ax' + bx + c>0 V xeR, then
(A) 13a - 5b + 2c > 0
(C) c>0,D <
(B) 13a – b + 2c > 0
(D) a + c>b, D<0​

Answer 1

Answer:

Roots of the quadratic equation ax2+bx+c=0 are imaginary.

⇒b2−4ac<0 -----(1)

Now, for the expression a2x2+abx+ac,

Δ=a2b2−4a3c=a2(b2−4ac)<0   from (1)

Since, discriminant value is less than zero, coefficient of x2 and expression always have same sign.

∴a2x2+abx+ac>0