Question

7х+у=95х+2у=9Решите пж

Answer 1

$\left \{ {{7x+y=9/*(-2)} \atop {5x+2y=9}} \right. \left \{ {{-14x-2y=-18} \atop {5x+2y=9}} \right. \\ -9x=-9 \\ x=1 \\ 5+2y=9 \\ 2y=9-5 \\ 2y=4 \\ y=2 \\ \left \{ {{x=1} \atop y=2}} \right.$

Answer 2

7х + у = 9    // * ( - 2)
5х + 2у = 9

- 14x  - 2y = - 18
5x + 2y = 9 
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-  14x + 5x = - 18 + 9
- 9x = - 9 
x = 1 

y = 9 - 7 = 2 

ОТВЕТ:
( 1; 2)