Question

3x+8y=-1
-3x+y=-17

Solve with addition method and get the points for x and y

Answer 1

`\left \{ {{3x+8y=-1} \atop {-3x+y=-14}} \right. \\+-------\\add\ both\ equations\\\\ 9y=-15 \ \ \ | divide\ by\ 9\\\\ y=-(15)/(9)=-(5)/(3)\\\\ 3x=-1-8y\ \ \| divide\ by\ 3\\\\ x=(-1-8y)/(3)=(-1-8*(-(5)/(3)))/(3)=(-1+(40)/(3))/(3)=(37)/(3)*(1)/(3)=(37)/(3)`

Answer 2

`3x+8y=-1 \\ \underline{-3x+y=-17} \\ 8y+y=-1-17 \\ 9y=-18 \\ y=(-18)/(9) \\ y=-2 \\ \\ -3x+y=-17 \\ -3x-2=-17 \\ -3x=-17+2 \\ -3x=-15 \\ x=(-15)/(-3) \\ x=5 \\ \\ \boxed{(x,y)=(5,-2)}`