We have,
x−3x−4+x−5x−6=0
⇒(x−3)(x−6)+(x−5)(x−4)(x−4)(x−6)=0
⇒x2−3x−6x+18+x2−5x−4x+20(x−4)(x−6)=0
⇒x2−9x+18+x2−9x+20=0
⇒2x2−18x+38=0
⇒x2−9x+19=0
Comparing that, ax2+bx+c=0 and we get,
a=1,b=−9,c=19
Using quadratic equation formula
x=−b±√b2−4ac2a
x=−(−9)±√81−4×1×192×1
x=9±√81−762
x=9±√52
Hence, this is the answer.