我有几道整式的加减计算题!

题目

我有几道整式的加减计算题!
1 (x的平方+5+4x)+(5x-4+2x的平方)
2 7x-(5x-5y)-y
3 2x-(3x-2y+2)+(3x-4y-1)
4 2x+2y-[3x-2(x-y)]
还有半个小时!好的我加!块块!

答案

1 (x²+5+4x)+(5x-4+2x²)
=x²+5+4x+5x-4+2x²
=(x²+2x²)+(4x+5x)+(5-4)
=3x²+9x+1
2 7x-(5x-5y)-y
=7x-5x+5y-y
=2x+4y
3 2x-(3x-2y+2)+(3x-4y-1)
=2x-3x+2y-2+3x-4y-1
=(2x-3x+3x)+(2y-4y)+(-2-1)
=2x-2y-3
4 2x+2y-[3x-2(x-y)]
=2x+2y-(3x-2x+2y)
=2x+2y-(x+2y)
=2x+2y-x-2y
=x