Question

(x-1)(2x-1)的五次方展开项中为什么三次项和一次项系数之和等于70?

Answer 1

(2x-1)^5=32x^5-80x^4+80x^3-40x^2+10x-1

(x-1)(2x-1)^5=32x^6-112x^5+160x^4-120x^3+50x^2-11x+1

答案算的有问题