计算x^2 + x - x分之1 + 1
问题描述：
计算x^2 + x - x分之1 + 1
答
(1)[1+(x-2分之1)]除以(2x-4)分之(x^2-1)
=(x-1)/(x-2) * 2(x-2)/(x+1)(x-1)
=2/(x+1)
[ 等于(x+1)分之2 ]
(2)[(x-y)^2+3(x^2-3分之1 y^2)]除以2x
=(x²+y²-2xy+3x²-y²)÷2x
=(4x²-2xy)÷2x
=2x-y