А
1)2y²-15y+18=2(y-1,5)(y-6)=(2y-3)(y-6)
D=225-144=81
y1=(15+9)/4=6
y2=(15-9)/4=1,5
3(y-2)(y+2)/[(2y-3)(y-6)]*(6-y)/(y+2)=-3(y-2)/(2y-3)=(3y-6)/(3-2y)
2)(3y-6)/(3-2y)+y/(3-2y)=(4y-6)/(3-2y)=-2(3-2y)/(3-2y)=-2
б
1)6y²+11y-2=6(y-1/6)(y+2)=(6y-1)(y+2)
D=121+48=169
y1=(-11-13)/12=-2
y2=(-11+13)/12=1/6
(y-2)/[(6y-1)(y+2)]+4/[(y-2)(y+2)]=(y²-4y+4+24y-4)/[(6y-1)(y²-4)]=
=(y²+20y)/[(6y-1)(y²-4)]
2)(y+20)/[y(y²-4)]*(6y-1)(y²-4)/[y(y+20)]=(6y-1)/y²
в
1)a²-3a+2=(a-2)(a-1)
a1+a2=3 U a1*a2=2⇒a1=-2 U a2=1
4a/[(a-2)(a-1)]+2/[(a-1)(a+1)]=(4a²+4a+2a-4)/[(a-2)(a²-1)]=
=(4a²+6a-4)/[(a-2)(a²-1)]=2(2a-1)(a+2)/[(a-2)(a²-1)]
4a²+6a-4=4(
D=36+64=100
a1=(-6-10)/8=-2
a2=(-6+10)/8=1/2
2)a²-a-2=(a-2)(a+1)
a1+a2=1 U a1*a2=-2⇒a1=-1 U a2=2
2(2a-1)(a+2)/[(a-2)(a-1)(a+1)] *(a-2)(a+1)/2(a+2)=(2a-1)/(a-1)
3)(2a-1)/(a-1)-a/(a-1)=(a-1)/(a-1)=1