(10y+1)⋅(2y−3)=(20y−4)(y+1) = 20y^2-30y+2y-3=20y^2+20y-4y-4 = -30y+2-3=20y-4y-4 = -28y-3=16y-4 = -28y-3=16y-4 = -28y-16y=-4+3 = -44y=-1 = .
(10y+1)⋅(2y−3)=(20y−4)(y+1) = 20y^2-30y+2y-3=20y^2+20y-4y-4 = -30y+2-3=20y-4y-4 = -28y-3=16y-4 = -28y-3=16y-4 = -28y-16y=-4+3 = -44y=-1 = .