Question

6. Eliminate the x in the following system of equations. What is the result when you add the two equations?X+y=2(3x – 4y = 270-7y = 20-7y = -25O 7 = 25O 7y=-21

Answer 1

We have the following system of equations:

$\begin{gathered} x+y=2, \\ 3x-4y=27. \end{gathered}$

We must eliminate x by summing the equations.

1) Before adding the equations, we multiply by -3 the first equation, we get:

$\begin{gathered} -3x-3y=-6, \\ 3x-4y=27. \end{gathered}$

2) Now, summing the equations, we get:

$\begin{gathered} (-3x-3y)+(3x-4y)=-6+27, \\ -7y=21. \end{gathered}$

Answer

-7y = 21