Question

Помогите пожалуйста, срочно!!!

Answer 1

Объяснение:

а)

$x = y \\ 3x + 2y = 5 \\ \\ 3y + 2y = 5 \\ 5y = 5 \\ y = 1 \\ x = 1$

ответ : (x,y) = (1,1)

б)

$x = 3y \\ x + y = 12 \\ \\ 3y + y = 12 \\ 4y = 12 \\ y = 3 \\ \\ x = 3(3) \\ x = 9$

ответ: (x,y) = ( 3,9)

в)

$x - 2y = 0 \\ x + y = 3 \\ \\ x = 0 + 2y \\ \\ 2y + y = 3 \\ 3y = 3 \\ y = 1 \\ \\ x + 1 = 3 \\ x = 3 - 1 \\ x = 2$

ответ: (x,y) = (1,2)

$4(x + 2y) = 5x + 6 \\ 3(2x - y) = 24y + 6 \\ \\ 4x + 8y = 5x + 6 \\ 4x + 8y - 5x = 6 \\ - x + 8y = 6 \\ \\ 6x - 3y = 24y + 6 \\ 6x - 3y - 24y = 6 \\ 6x - 27y = 6 \\ \\ - x + 8y = 6 \\ 6x - 27y = 6 \\ \\ - 6x + 48y = 36 \\ 6x - 27y = 6 \\ \\ - 6x + 48y + 6x - 27y = 36 + 6 \\ 21y = 42 \\ y = 2 \\ \\ - x + 16 = 6 \\ - x = 6 - 16 \\ - x = - 10 \\ x = 10$

ответ : (x,y) = (2,10)

$5(x - 3y) = 2x + 7 \\ 3(x + 6y) = 9y + 15 \\ \\ 5x - 15y = 2x + 7 \\ 5x - 15y - 2x= 7 \\ \\ 3x - 15y = 7 \\ \\ 3x + 18y = 9y + 15 \\ 3x + 18y - 9y = 15 \\ \\ 3x + 9y = 15 \\ \\ 3x - 15y = 7 \\ 3x + 9y = 15 \\ \\ 3x - 15y - 3x - 9y = 7 - 15 \\ - 24y = - 8 \\ y = \frac{ - 8}{ - 24} \\ y = \frac{1}{3} \\ \\ \\ 3x + 9( \frac{1}{3} ) = 15 \\ 3x + 3 = 15 \\ 3x = 15 - 3 \\ 3x = 12 \\ x = 4$

ответ ; ( x,y) = ( 4 , 4/3)