RRB Group-D Model Paper 16 with answers for online practice

CONCEPT:
Roots of a quadratic equation satisfy the equation, so by putting the value of one root,
One can find the unknown variable and hence the other root.
CALCULATION:
Let us put x = 3 in the equation ${\mathit{x}}^2$ – 12x + k = 0,
⇒ 9 – 36 + k = 0
⇒ k = 27
Putting the value of k in the equation,
we get: ${\mathit{x}}^2$ – 12x + 27 = 0
⇒ ${\mathit{x}}^2$ – 9x – 3x + 27 = 0
⇒ x(x – 9) – 3 (x – 9) = 0
⇒ (x – 3)(x – 9) = 0
⇒ x = 3 and 9
∴ Other root of the equation is 9