1)3x(3x+7)-(3x+1)²=9x²+21x-9x²-6x-1=15x-1
2)(y-2)(y+3)-(y-1)²=y²+3y-2y-6-y²+2y-1=3y-7
3)(p+1)²-(p+2)²=p²+2p+1-p²-4p-4=-2p-3
4)3(2a-5b)²-12(a-b)²=12a²-60ab+75b²-12a²+24ab-12b²=-36ab+63b²
5)(3x²+4)²+(3x²-4)²-2(5-3x²)(5+3x²)=9x^4+24x²+16+9x^4-24x²+16-50+18x²=
=18x^4+18x²-18