计算3(2-y)²-4(y+5)² 因式分解:5(a-1)²-10(1-a) 大师快来!

问题描述:

计算3(2-y)²-4(y+5)² 因式分解:5(a-1)²-10(1-a) 大师快来!

3(2-y)²-4(y+5)² =3(4-4y+y²)-4(y²+10y+25)=12-12y+3y²-4y²-40y-100=-y²-52y-885(a-1)²-10(1-a) =5(a-1)²+10(a-1)=(a-1)(5a-5+10)=(a-1)(5a+5)=5(a-1)(a+1)