Solve each of the following equations by using the method of completing the square:
7x2 + 3x - 4 = 0
Given: 7x2 + 3x - 4 = 0
49x2 + 21x - 28 = 0 (multiplying both sides by 7)
(adding 
on both sides)
using a2 + 2ab + b2 = (a + b)2
(taking square root on both sides)
Hence the roots of equation are 
8