l 3x -2y-4.5 l +√5x+3y-45.5 =0 求4x＋7y的平方根

因为|3x -2y-4.5|+√(5x+3y-45.5)=0,又因为|3x -2y-4.5|≥0,√(5x+3y-45.5)≥0,所以|3x -2y-4.5|=0,√(5x+3y-45.5)=0,所以有3x-2y-4.5=0,(1)5x+3y-45.5=0,(2)(1)*3,得9x-6y-13.5=0,(3)(2)*2,得10x+6y-91=0,(4)(3)+(4...