Question

Розвяжіть систему рівнянь способом підбора в завдані 2Б

Answer 1

Объяснение:

2б

х/3 - у/2 = 5/6 | * 6

х/9 + 5у/6 = 23/18 | * 18

2х - 3у = 5 | : 2

2х + 15у = 23

х - 1,5у = 2,5

2х + 15у = 23

х = 2,5 + 1,5у

2х + 15у = 23

1)

2х + 15у = 23

2(2,5 + 1,5у) + 15у = 23

5 + 3у + 15у = 23

3у + 15у = 23 - 5

18у = 18

у = 18 : 18

у = 1

2)

х = 2,5 + 1,5у

х = 2,5 + 1,5 * 1

х = 2,5 + 1,5

х = 4

Ответ: (4; 1)

Answer 2

$\displaystyle\bf\\\left \{ {{\dfrac{x}{3}-\dfrac{y}{2} =\dfrac{5}{6} } \atop {\dfrac{x}{9} +\dfrac{5y}{6} =\dfrac{23}{18} }} \right. \\\\\\\left \{ {{\dfrac{x}{3}\cdot 6-\dfrac{y}{2} \cdot 6=\dfrac{5}{6} \cdot 6 } \atop {\dfrac{x}{9}\cdot 18 +\dfrac{5y}{6}\cdot 18 =\dfrac{23}{18} \cdot 18}} \right.\\\\\\\left \{ {{2x-3y=5 \atop {2x+15y=23}} \right. \\\\\\\left \{ {{2x=3y+5} \atop {3y+5+15y=23}} \right. \\\\\\\left \{ {{2x=3y+5} \atop {18y=18}} \right.$

$\displaystyle\bf\\\left \{ {{2x=3\cdot 1+5} \atop {y=1}} \right. \\\\\\\left \{ {{2x=8} \atop {y=1}} \right.\\\\\\\left \{ {{x=4} \atop {y=1}} \right. \\\\\\Otvet \ : \ \Big(4 \ ; \ 1\Big)$