解方程,{(x+2)²-(y+4)²=(x+y)(x-y),x-3y=-2,运用平方差

问题描述:

解方程,{(x+2)²-(y+4)²=(x+y)(x-y),x-3y=-2,运用平方差

x-3y=-2得x=3y-2(x+2+y+4)×(x+2-y-4)=x²-y²(x+y+6)×(x-y-2)=x²-y²x²-xy-2x+xy-y²-2y+6x-6y-12=x²-y²x²-y²-4x-8y=x²-y²-4x-8y=0带入x=3y-2-4...