Question

One of the roots of quadtratic equation k²-7x+12=0 is 3; the value of k is​

Answer 1

Answer:

Find k, if one of the roots of the quadratic equation kx2 – 7x + 12 = 0 is 3.

3. Find k, if one of the roots of the quadratic equation kx2 – 7x + 12 = 0 is 3.

Sol. kx2 – 7x + 12 = 0

∵ 3 is one of the root of the quadratic equation, kx2 – 7x + 12 = 0

∴ x = 3 satisfies the equation,

Substituting x = 3 in equation we get,

k (3)2 – 7 (3) + 12 = 0

∴ 9k – 21 + 12 = 0

∴ 9k – 9 = 0

∴ 9k = 9

∴ k = 9/9

∴ k = 1