(y-3)²-(y-2)(y+2) если y=-2,5
Y²-6y+9-y²+4=13-6y 13-6(-2.5)=13+1.5=14.5
Y2-6y+9-(y2-4)=y2-6y+9-y2+4=-6y+13=-6(-2,5)+13=15+13=28