Let x−12x−3= a …….(i)
⇒a−a4=3⇒aa2−4=3⇒a2−4=3a⇒a2−3a−4=0⇒a2−4a+a−4=0⇒a(a−4)+1(a−4)=0⇒(a+1)(a−4)=0⇒a=−1 or a=4.
Substituting value of a = -1 in (i) we get,
⇒x−12x−3=−1⇒2x−3=−1(x−1)⇒2x−3=−x+1⇒2x+x=1+3⇒3x=4⇒x=34⇒x=131
Substituting value of a = 4 in (i) we get,
⇒x−12x−3=4⇒2x−3=4(x−1)⇒2x−3=4x−4⇒4x−2x=−3+4⇒2x=1⇒x=21.
Hence, x = 131,21.