Solving Systems by Substitution

When solving the system of equations by substitution, and looking for a generic answer for x or y, what should be the first step?

y = 3x - 11

2x + 3y = 0

The first step in solving a system of equations using the substitution method is __________.

• get x by itself
• get y by itself
• get either variable by itself
• add the equations together

When solving the system of equation below by substitution, which is a generic answer for either x or y?

3x + 2y = 8

-x + y = -11

• $x=y-11$

• $-x=-y-11$

• $-y=-x+11$

• $y=x-11$

When solving the system below by substitution, what does the equation look like after substituting the generic answer of y?

y = 3x - 8

y = 4 - x

• $3x-8=4-x$

• $3\left(4-x\right)=3x-8$

• $4-3x-8=3x-8$

• $4-x=3\left(x-8\right)-x$

When solving systems of equations by substitution, what could represent a generic answer for y?  Select all that apply.

•  $y=x$  

•  $y=.75$  

•  $y=\frac{1}{2}$  

•  $y=2x-9$  

Which represents a real answer for x or y?