1) (6a-7)²-(4a-3)²=36a²-84a+49-(16a²-24a+9)=
=36a²-84a+49-16a²+24a-9=20a²-60a+40=20*(a²-3a+2)
a²-3a+2=0 D=1 a₁=2 a₂=1 ⇒
20*(a²-3a+2)=20*(a-2)*(a-1).
2) (6a-7)²-(4a-2)²=(6a-7+4a-2)*(6a-7-4a+2)=(10a-9)*(2a-5).
(2у-3)(3у+1)+2(у-5)(у+5)= 2(1-2у)²+6у
6y²-7y-3+2y²-50=2-8y+8y²+6y
8y²-7y-53=8y²-2y+2
5y=-55 |÷5
y=-11.