Решите пример 4х/у × у/12х

4 x/y × y/12x = 4x × 12x (т.к. y сокращаются) = 48 x²

1)  3x-y=22x+2y=5y=3x - 22x+2(3x - 2)=5 y=3x - 2 2x + 6x - 4 = 5 y=3x - 2 8x=9 y=3x - 2 x= 9/8 y=3* 9/8 - 2 x= 9/8 y = 11/8 x = 9/8 проверка 3 * 9/8 - 11/8 = 2 27/8 - 11/8 = 2 16/8 = 2 2=2 2) 3x-5y=4 2x+6y=35x + y = 72x + 6y = 3y= 7- 5x2x + 6y = 3y= 7 - 5x2x + 6(7-5x) = 3y= 7 - 5x 2x + 42 - 30x = 3 y= 7 - 5x 42 - 3 = 30x - 2x y= 7 - 5x 28x = 39 y= 7 - 5x x = 39/28 y= 7 - 5* 39/28 x= 39/28 y= 196/28 - 195/28 x = 39/28 y=1/28 x=39/28 проверка 3* 39/28 - 5* 1/28 = 4117/28 - 5/28 = 4112/28 = 44 = 43)  4x+3y=2 5x-2y=39x + y = 55x - 2y = 3y= 5 - 9x5x - 2* (5 - 9x) = 3y= 5 - 9x 5x - 10 + 18x = 3 y= 5 - 9x 23x = 3 + 10 y= 5 - 9x 23x = 13 y= 5 - 9x x=13/23 y= 5 - 9* 13/23 x= 13/23 y= 115/23 - 117/23 x = 13/23 y= -2/23 x= 13/23 проверка 4* 13/23 + 3* (-2/23) = 252/23 - 6/23 = 2 46/23=2 2=2