х²+5х-14
________
х²-6х+8

(x²+5х-14)/(х²-6х+8)=(x-2)(x+7) / (x-4)(x-2) =(x-7)/(x-4)

х2+5х-14=0D=b2-4acD=5(2)-4×1×(-14)=25+56=81х= -b+-√D÷2aх= -5+-√81÷2×1= -5+-9÷2х(1)= -5-9÷2= -14÷2= -7х(2)= -5+9÷2= 4÷2= 2х2-6х+8=0D= 6(2)-4×1×8=36-32=4х= 6+-√4÷2×1= 6+-2÷2х(1)= 6-2÷2=2х(2)= 6+2÷2=4