RRB Group-D Model Paper 19 with answers for online practice

Tips & Tricks
Given:
${\mathit{x}}^2$ + 7 x + 12 = 0
Formula used:
x = [−b±( $\sqrt{{\mathit{b}}^2-4\mathit{a}\mathit{c}}$ )]/2a
Calculation:
Here in this equation, ${\mathit{x}}^2$ + 7 x + 12 = 0
a = 1, b = 7, c = 12
x = [−7±( $\sqrt{7^2-4\times 1\times 12}$ )]/2 × 1
x = (-7 ± 1)/2
x = -3, -4
Short Trick:
The equation ${\mathit{x}}^2$ + 7 x + 12 = 0 can be written as
${\mathit{x}}^2$ + 7 x + 12 = 0 ⇒ ${\mathit{x}}^2$ + 3 x + 4x + 12 = 0
⇒ (x + 3)(x + 4) = 0
∴ x = -3, -4