帮我解几道数学题,(1)(x+y+z)(-x-y+z)(2)[(x+y)^2-(x-y)^2]÷(2xy)(3)a^2(a+1)^2-2(a^2-2a+4)(4)一块直径为a+b的圆形木版,从中挖去直径分别为a与b的两个圆,则剩下的木版的面积是＿＿＿＿(5)3(2x+1)(2x-1)-4(3/2x-3)(3/2x

Question

帮我解几道数学题,
(1)(x+y+z)(-x-y+z)
(2)[(x+y)^2-(x-y)^2]÷(2xy)
(3)a^2(a+1)^2-2(a^2-2a+4)
(4)一块直径为a+b的圆形木版,从中挖去直径分别为a与b的两个圆,则剩下的木版的面积是＿＿＿＿
(5)3(2x+1)(2x-1)-4(3/2x-3)(3/2x+3)

Answer 1

1.z平方-(x+y)平方