Solving Systems of 2 Linear Equations by Substitution

Which equation is easiest to solve for x?

• $x+4y=30$

• $2x+5y=10$

• $-5y=12+\frac{1}{2}x$

• $y=3x+21$

Which equation is easiest to solve for y?

• $\frac{1}{3}y+x=15$

• $5x+2y=9$

• $3x-y=0$
  

• $5+6y=12x$

What is the first step to solve the following system?

 $6x-9=y$  & $y=-3x$  

•  $6x=y+9$  

•  $6x-9=-3x$  

•  $\frac{y}{-3}=x$  

•  $y=y$  

Identify the mistake made in solving the following system of equations:  $4x+2y=6$  &  $3x+y=9$  

• Step 1: Solve for x first.

• Step 2:  $4\left(9-3x\right)+2y=6$  

• Step 3:  $3\left(6\right)+y=9$  

• Step 3:  $4\left(6\right)+2y=6$  

Solve the system of equations by substitution:  $x=17-4y$  &  $y=x-2$  

• (3, -1)

• (1, 3)

• (3, 5)

• (5, 3)