y有-7,x∈（-∞,-2】,2x-3,x∈(-2,5】,7,x∈（5,＋∞）这几个函数,怎么画图像并求y的值域?

化简3(x-y)-7(x--y)+2(y-x) 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 联立方程 有的话 x(x-y)2-(y-x)3 [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x 25（x-2y)平方-4(y-2x)平方答案是3(3x-4y)(x-8y)还是21(x-2y)2还是（7x-6y）有（3x-14y) (-3x+7y)(-7y-3x)-(x-3y)(2x+3y) 18(x+y)^8(x-y)^7÷[3(x+y)^3(x-y)^3]^2 3(x-y)^2-7(x-y)+8(y-x)^2+6(y-x)合并同类项. 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 计算：(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2 2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方 计算(x-y)^7÷(y-x)^6+9-x-y)^3÷(x+y)^2 化简:3(x-y)²-7(x-y)+ 2(x-y)²+5(x-y) 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) y=-1/3x,y=2x,y=7/2x,y=-5x的图像哪个最靠近Y轴,有什么规律?