Помогите пожалуйста с алгеброй?? Нужно решить методом алгебраического сложения

.14

 {x – 3y = 15 | • (–2),

{2x + 5y = –3. 

 + {–2x + 6y = –30,

+ {2x + 5y = –3. 

11y = –33,
y = –3.

Если y = –3, то
2x + 5 • (–3) = –3,
2x = –3 + 15,
x = 6.

Ответ: (6; –3).

.15

 {2x + 3y = 7,

{x – 2y = 14 | • (–2). 

 + {2x + 3y = 7,

+ {–2x + 4y = –28. 

7y = –21,
y = –3.

Если y = –3, то
2x + 3 • (–3) = 7,
2x = 7 + 9,
x = 8.

Ответ: (8; –3).

.16

 {4x – 3y = 15,

{2x – 6y = 2 | : (–2). 

 + {4x – 3y = 15,

+ {–x + 3y = –1. 

3x = 14,
x = 14/3.

Если x = 14/3, то
2 • 14/3 – 6y = 2,
–6y = 2 – 28/3,
y = 11/9.

Ответ: (14/3; 11/9).

.17

 {x – 2y = –2 | • (–2),

{2x + 5y = 5. 

 + {–2x + 4y = 4,

+ {2x + 5y = 5. 

9y = 9,
y = 1.

Если y = 1, то
x – 2 • 1 = –2,
x – 2 = –2,
x = 0.

Ответ: (0; 1).