Question

Срочно,,,,,,,,розв'язати систему методом додавання (2x+9y=2
(8x-15y=25

Answer 1

$\displaystyle\bf\\\left \{ {{2x+9y=2 \ |\cdot(-4)} \atop {8x-15y=25}} \right.\\\\\\+\left \{ {{-8x-36y=-8 } \atop {8x-15y=25}} \right. \\----------\\-51y=17\\\\y=17:(-51)=-\frac{1}{3} \\\\2x=2-9y=2-9\cdot\Big(-\frac{1}{3} \Big)=2+3=5\\\\x=5:2=2,5\\\\\\Otvet \ : \ \Big(2,5 \ ; \ -\frac{1}{3}\Big)$