Question

Find a pair of numbers that is a member of both -3x + 3y = 36 and -2x - y = 12

Answer 1

x = -8 and y = 4

(-8, 4)

Step-by-step explanation:

Given the below equations;

`\begin{gathered} -3x+3y=36 \\ -2x-y=12 \end{gathered}`

Let's go ahead and solve simultaneously using the substitution method.

From the 2nd equation, we have that;

`\begin{gathered} -y=2x+12 \\ y=-2x-12 \end{gathered}`

Let's put y = -2x - 12 into the 1st equation and solve for x;

`\begin{gathered} -3x+3(-2x-12)=36 \\ -3x-6x-36=36 \\ -9x=72 \\ x=-(72)/(9) \\ \therefore x=-8 \end{gathered}`

Since x = -8, let's put this into y = -2x - 12 and find y;

`\begin{gathered} y=-2(-8)-12 \\ y=16-12 \\ \therefore y=4 \end{gathered}`