X^2+2x-3=-3, x^2+2x-3+3=0, x^2+2x=0, x(x+2)=0. x=0 или (x+2)=0. x1=0, x2=-2. Ответ: x1=0, x2=-2.
400кг - 176кг 400кг-176кг
325кг - хкг 400х=325*176 хкг - 308кг
400х=57200 176х=123200
х=143 х=700
4 1/9 : х = 7,4,
х = 4 1/9 : 7,4,
х = 37/9 : 74/10,
х = 37/9 * 10/74,
х = 5/9,
х : 7,5 = 6/17,
х = 7,5 * 6/17,
х = 75/10 * 6/17,
х = 45/17,
х = 2 11/17,
9 2/11х = 10,1,
х = 10,1 : 9 2/11,
х = 101/10 : 101/11,
х = 101/10 * 11/101,
х = 11/10,
х = 1 1/10 (или 1,1)