Question

помогите решить систему уравнений$\left \{ {{2x+5y=9} \atop {3x+y=7}} \right.$

Answer 1

$\displaystyle\bf\\\left \{ {{2x+5y=9} \atop {3x+y=7} \ |\cdot(-5)} \right. \\\\\\+\left \{ {{2x+5y=9} \atop {-15x-5y=-35}} \right. \\------------\\2x+5y-15x-5y=9-35\\\\-13x=-26\\\\x=2\\\\y=7-3x=7-3\cdot 2=7-6=1\\\\Otvet \ : \ (2 \ ; \ 1)$

Answer 2

Ответ:

{

3x+y=7 ∣⋅(−5)

2x+5y=9

+{

−15x−5y=−35

2x+5y=9

−−−−−−−−−−−−

2x+5y−15x−5y=9−35

−13x=−26

x=2

y=7−3x=7−3⋅2=7−6=1

text\Otvet : (2 ; 1)