We have
4x2−4ax+(a2−b2)=0
Here, Constant term =(a2−b2)=(a−b)(a+b)
and coefficient of the middle term =−4a
Also. coefficient of the middle term −4a=−[2a+2b+2a−2b]=−[2(a+b)+2(a−b)]
∴4x2−4ax+(a2−b2)=0
⇒4x2−[2(a+b)+2(a−b)]x+(a+b)(a−b)=0
⇒4x2−2(a+b)x−2(a−b)x+(a+b)(a−b)=0
⇒[4x2−2(a+b)x]−[2(a−b)x−(a+b)(a−b)]=0
⇒2x[2x−(a+b)]−(a−b)[2x−(a+b)]=0
⇒[2x−(a+b)][2x−(a−b)]=0
⇒[2x−(a+b)]=0or[2x−(a−b)]=0
⇒2x=a+bor2x=a−b