Question

Solve the system of equations.

2x+7y=3
x=-3y
(3,-9)
(-1,3)
(3,-1)
(-9,3)

Answer 1

Answer: (-9, 3)

Explanation:

This problem works best with substitution.

To do a system of equations with substitution, solve for the first variable in one of the equations, then substitute the result into the other equation.

Since the second equation already gives us what x is (-3y) we can easily substitute this into the first equation. (2x + 7y = 3)

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`\left \{ {{2x+7y=3} \atop {x=-3y}} \right.`

`2(-3y)+7y=3`

`-6y+7y=3`

Combine the like terms.

`y=3`

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Since we have y, we need to find x now.

Because we already used the first equation to find y, plug y into the SECOND equation.

`x= -3(3)\\`

`x = -9`

Done!

(-9, 3)