Question

初二因式分解的题目

1.(x+y)²-4（x+y-1)
2.(x-y)²+4xy
3.(x-1)(x+3)+1

Answer 1

1.(x+y)²-4（x+y-1)
=(x+y)²-4(x+y)+4
=(x+y)²-2×2(x+y)+2²
=(x+y-2)²

2.(x-y)²+4xy
=x²-2xy+y²+4xy
=x²+2xy+y²
=(x+y)²

3.(x-1)(x+3)+1
=x²+2x+1-3
=(x+1)²-3
=(x+1)²-(√3)²
=(x+1+√3)(x+1-√3)

Answer 2

1 原式=(x+y-2)²
2 原式=(x+y)²
3 原式=(x+1+√3)(x+1-√3)

Answer 3

.1,(x+y)²-4（x+y-1)=.(x+y)²-4(x+y)+4=(x+y-2)²
2,.(x-y)²+4xy=x²-2xy+y²+4xy=x²+2xy+y²=(x+y)²