1
-7x²-13x+2=0
D=169+56=225
x1=(13-15)/(-14)=1/7
x2=(13+15)/(-14)=-2
x(7x-1)/[-7(x-1/7)(x+2)]=x(7x-1)/[-(7x-1)(x+2)]=-x/9x+2)
2
9a²-9a+2=0
D=81-72=9
a1=(9-3)/18=1/3
x2=(9+30/18=2/3
1-3a+b-3ab=(1-3a)+b(1-3a)=(1-3a)(1+b)
9(a-1/3)(a-2/3)/[(1-3a)(1+b)=(3a-1)(3a-2)/[-(3a-1)(b+1)]=(2-3a)/(b+1)
3
2-5m-2n+5mn=(2-5m)-n(2-5m)=(2-5m)(1-n)
10m²-9m+2=0
D=81-80=1
m1=(9-1)/20=0,4
m2=(9+1)/20=0,5
(2-5m)(1-n)/[10(m-0,4)(m-0,5)]=(5m-2)(n-1)/[(5m-2)(2m-1)]=(n-1)/(2m-1)