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Mathematics

Assertion (A): The quadratic equation 3kx2 - 4kx + 4 = 0 has equal roots, if k = 3.

Reason (R): For equal roots of a quadratic equation, we must have D = 0.

  1. Both A and R are true, and R is the correct explanation of A.

  2. Both A and R are true, but R is not the correct explanation of A.

  3. A is true, but R is false.

  4. A is false, but R is true.

Quadratic Equations

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Answer

Given,

⇒ 3kx2 - 4kx + 4 = 0

when k = 3

⇒ 3 × (3) × x2 - 4 × (3) × x + 4 = 0

⇒ 9x2 - 12x + 4 = 0

Comparing 9x2 - 12x + 4 = 0 with ax2 + bx + c = 0 we get,

a = 9, b = -12 and c = 4.

We know that,

Discriminant (D) = b2 - 4ac

= (-12)2 - 4 × (9) × (4)

= 144 - 144 = 0.

Therefore, the equation has rational and equal roots.

So, Assertion (A) is true.

The Discriminant is given by b2 - 4ac, if the discriminant of any quadratic equation is zero. Then it is said have equal and real roots.

So, Reason (R) is true.

Thus, both A and R are true and R is the correct explanation of A.

Hence, option 1 is the correct option.

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