Question

упростите выражение: 1.) (a+2)(a-5)-3a(1-2a) 2.)(a-7)(3a-2)-(5a+1)(2a-4)

Answer 1

1)(a+2)(a-5)-3a(1-2a)=a^2 -5a+2a-10-3a+6a=a^2 -10

2)(a-7)(3a-2)(5a+1)(2a-4)=3a^2 -2a-21a+14-(10a^2 -20a+2a-4)=3a^2 -2a-21a+14-10a^2 +20a-2a+4=-7a^2 -5a+10