A) x^2/(x^2-9))-((5x-6)/(x^2-9)=0
(x^2-5x+6)/(x^2-9)=0
x^2-5x+6=0
D=25-24=1, x1=(5+1)/2=3
x2=(5-1)/2=2
b) (4(x+3)+5x)/(x(x+3)=3
4x+12+5x=3x(x+3)
9x+12-3x^2-9x=0
-3(x^2-4)=0
-3(x-2)(x+2)=0
x1=2, x2=-2
в) (4x+60)/x=x
4x+60=x^2, x^2-4x-60=0
D=16-4*(-60)=256=16^2
x1=(4+16)/2=10
x2=(4-16)/2=-6