若4X﹣3Y-6Z=0,X+2Y-7Z=0,（XYZ不等于0）,求（5X^2+2Y^2-Z^2）/(2X^2-3y^2-10Z^2)的值?

若4X﹣3Y-6Z=0,X+2Y-7Z=0,（XYZ不等于0）,求（5X^2+2Y^2-Z^2）/(2X^2-3y^2-10Z^2)的值?
若4X﹣3Y-6Z=0,X+2Y-7Z=0,（XYZ不等于0）,求（5X^2+2Y^2-Z^2）/(2X^2-3y^2-10Z^2)的值?

若4X﹣3Y-6Z=0,X+2Y-7Z=0,（XYZ不等于0）,求（5X^2+2Y^2-Z^2）/(2X^2-3y^2-10Z^2)的值?
4X﹣3Y-6Z=0 (1) X+2Y-7Z=0 (2) (1) - (2) * 4 ==> -11y + 22z = 0 ==> y = 2Z (1) * 2 + (2) * 3 ==> 11x - 33z =0 ==> x = 3Z (5X^2+2Y^2-Z^2）/(2X^2-3y^2-10Z^2) = [5 * (3z)^2 + 2 * (2z)^2 - z^2)] / [ (2 * (3z)^2 - 3 * (2z)^2 - 10z^2] = [ 5 * 9 + 2 * 4 - 1] / [2 * 9 - 3 * 4 - 10] = [45 + 6 - 1] / [18 - 12 - 10] = 50 / (-4) = - 25/2