Question

Solve the system of equations using substitution or elimination: 2x – y = 0 x + 3y = -14

Answer 1

Answer:

x = -2 , y= -4

Step-by-step explanation:

$\begin{bmatrix}2x-y=0\\ x+3y=-14\end{bmatrix}\\\\\mathrm{Isolate}\:x\:\mathrm{for}\:2x-y=0:\quad x=\frac{y}{2}\\\\\mathrm{Subsititute\:}x=\frac{y}{2}\\\\\begin{bmatrix}\frac{y}{2}+3y=-14\end{bmatrix}\\\\\mathrm{Simplify}\\\\\begin{bmatrix}\frac{7y}{2}=-14\end{bmatrix}\\\\\mathrm{Isolate}\:y\:\mathrm{for}\:\frac{7y}{2}=-14:\quad y=-4\\\\\mathrm{For\:}x=\frac{y}{2}\\\\\mathrm{Subsititute\:}y=-4\\x=\frac{-4}{2}\\\\\frac{-4}{2}=-2\\\\x=-2,\:y=-4$

Answer 2

Answer:

(-2,-4)

Step-by-step explanation:

2x-y=0

-2(x+3y=-14)

-2x-6y=28

x terms cancel

-y+-12y=-13y

0+28=28

-7y=28

28/-7

y=-4

plug into the orginal equation

2x-(-4)=0

simply: 2x+4=0

elimante the 4

2x=-4

divide by 2

x=-2