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1a)5y(3y-2)-(y-1)(y+1)=15yˇ2-10y-yˇ2+1=14yˇ2-10y+1
1b)6(c+d)ˇ2-12cd=6cˇ2+12cd+6dˇ2-12cd=6cˇ2+6dˇ2
1c)(d-8)(d+4)+(d-5)ˇ2=dˇ2-4d-32+dˇ2-10d+25=2dˇ2-14d-7
2a)bˇ3-36b=b(bˇ2-36)=b(b+6)(b-6)
2b)-2aˇ2+8ab-8bˇ2=-2(aˇ2-4ab+4bˇ2)=-2(a-2)(a-2)=-2(a-2)ˇ2
3)bˇ2-9+3(bˇ2-9)=4bˇ2-36
4(-2)ˇ2-36=16-36=-20
4a)(y-3)ˇ2-16yˇ2=(y-3+4y)(y-3-4y)=(5y-3)(-3y-3)=-3(y+1)(5y-3)
4b)xˇ2-yˇ2-(x+y)=(x+y)(x-y)-(x+y)=(x+y)(x-y-1)
5)a4-1=(aˇ2+1)(aˇ2-1)=(a-1)(a+1)(aˇ2+1)=(a-1)(aˇ3aˇ2+a+1)