Question

数学计算题(多项式乘以多项式)1.(X-3)(X-5)-3(X-1)(X+3)2.(a+2b-3)(a-2b+3)3.(

Answer 1

用待定系数法

（X^2+2X+3）（ax+b）=ax^3+(b+2a)x^2+(3a+2b)x+3b

所以(3a+2b)=0

b+2a=1

解得a=2

b=-3