Question

For what value of r the quadratic equation rx^2+4x-4=0 has real roots.
A) r^3>-1, B) r_>-1, C) r^3=1, D) r_<1

Answer 1

Answer:

(B) r ≥ -1

Step-by-step explanation:

Given a quadratic equation such that,

rx^2 + 4x -4 = 0.

Given that,

The roots are real.

To find the value of r.

We know that,

For real roots, Descriminant, D ≥ 0.

Also, we know that,

D = b^2 - 4ac

Substituting the values, we get,

=> b^2 - 4ac ≥ 0

=> 4^2 - 4(r)(-4) ≥ 0

=> 16 + 16r ≥ 0

=> 16(r+1) ≥ 0

=> r + 1 ≥ 0

=> r ≥ -1

Hence, correct answer is (B) r ≥ -1.