Question

completing square method with an example (third term)

Answer 1

listen friend ,it is very easy method try to understand it ,

let we take the example 9x^2-15x+6=0 

step1
always make sure that the coefficient of x^2 is 1 or make it as 1 by dividing the number on both sides .
so we get ,
x^2-15/9x+6/9=0
x^2-5/3x+2/3=0
x^2-5/3x=-2/3

step 2
now add (coefficient of x)^2 on both sides with multiplying the denominator by 2
x^2-5/3x+(5/6)^2=(5/6)^2-2/3


step 3
now ,we can express 5/3x as 2(5/6)x,so as to make LHS as (a+ or -b)^2

x^2-2(5/6)x+(5/6)^2=(5/6)^2-2/3
so,
(x-5/6)^2=1/36
x-5/6=+-1/6
x=5/6-1/6=2/3 or 5/6+1/6=1