Tentukan hasil dari1 (2x+7) (x-5)2 (y+3) (y+7)3 (2+4) (2z-10)4 (a-5) (a-8)

1 2x²-10x+7x-35= 2x²-3x-35
2 y²+7y+3y+21=y²+10y+21
3 4z-20+8z-40=12z-20
4 a²-8a -5a+13=a²-13a+13

1. (2x+7)(x-5) = 2x²-10x+7x-35 =2x²-3x-35
2. (y+3)(y+7) = y²+7y+3y+21 = y²+10y+21
3. (2+4)(2z-10) = 4z-20+4z-40 = 8z-60
4. (a-5)(a-8) = a²-8a-5a+40 = a²-13a+40