Question

помогите пожалуйста.​

Answer 1

1)2x + y = 8 2x = 8 - y
2x - y = 0 2x - y = 0

8 - y - y = 0 2x = 8 - 4
-2y = -8 2x = 4
y = 4 x = 2

2)7x - 5y = -26 7x - 5y = -26
y - 2x = 8 y = 8 + 2x

7x - 5(8 + 2x) = -26 y = 8 + (2 * -14/3)
7x - 40 - 10x = -26 y = -4/3
-3x = -26 + 40
-3x = 14
x = -14/3

3)x + 2y = 0 x = -2y
5x + y = -18 5x + y = -18

-10y + y = -18 x = -4
-9y = -18
y = 2

Answer 2

$1)\; \; \left \{ {{2x+y=8} \atop {2x-y=0}} \right.\; \oplus \; \left \{ {{4x=8} \atop {y=2x}} \right.\; \left \{ {{x=2} \atop {y=4}} \right.\; \; \Rightarrow \; \; \; (2,4)\\\\\\2)\; \; \left \{ {{7x-3y=-26} \atop {y-2x=8}} \right.\; \left \{ {{7x-3(2x+8)=-26} \atop {y=2x+8}} \right.\; \left \{ {{x-24=-26} \atop {y=2x+8}} \right.\; \left \{ {{x=-2} \atop {y=4}} \right.\; \; \Rightarrow \; \; (-2,4)$

$3)\; \; \left \{ {{x+2y=0} \atop {5x+y=-18}} \right.\; \; \left \{ {{x=-2y} \atop {-10y+y=-18}} \right. \; \left \{ {{x=-2y} \atop {-9y=-18}} \right.\; \left \{ {{x=-4} \atop {y=2}} \right. \; \; \Rightarrow \; \; (-4,2)$