来自齐本胜的问题
1.已知-3y=x+2z,求x^2-9y^2+4z^2+4xz的值.2.已知x不等于y,且x^2-x=13,y^2-y=13,求x+y-7的值.
1.已知-3y=x+2z,求x^2-9y^2+4z^2+4xz的值.
2.已知x不等于y,且x^2-x=13,y^2-y=13,求x+y-7的值.
1回答
2020-05-0216:02
1.已知-3y=x+2z,求x^2-9y^2+4z^2+4xz的值.2.已知x不等于y,且x^2-x=13,y^2-y=13,求x+y-7的值.
1.已知-3y=x+2z,求x^2-9y^2+4z^2+4xz的值.
2.已知x不等于y,且x^2-x=13,y^2-y=13,求x+y-7的值.
1.已知-3y=x+2z,求x^2-9y^2+4z^2+4xz的值.x^2-9y^2+4z^2+4xz=(x+2z)^2-9y^2=(-3y)^2-9y^2=02.已知x不等于y,且x^2-x=13,y^2-y=13,求x+y-7的值.x^2-x=13,y^2-y=13,两式相减的x^2-x-y^2+y=0分解得,(x+y-1)(x-y)=0因为...