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

Tips & Tricks
Given:
x2 + 7 x + 12 = 0
Formula used:
x = [−b±( √b2−4ac )]/2a
Calculation:
Here in this equation, x2 + 7 x + 12 = 0
a = 1, b = 7, c = 12
x = [−7±( √72−4×1×12 )]/2 × 1
x = (-7 ± 1)/2
x = -3, -4
Short Trick:
The equation x2 + 7 x + 12 = 0 can be written as
x2 + 7 x + 12 = 0 ⇒ x2 + 3 x + 4x + 12 = 0
⇒ (x + 3)(x + 4) = 0
∴ x = -3, -4