Chapter 5.2-5.3 Quiz

Get y alone:  $2x+3y=9$  

•  $y=\frac{2}{3}x-9$  

•  $y=\frac{3}{2}x-3$  

•  $y=-\frac{2}{3}x+3$  

•  $y=-\frac{2}{3}x+9$  

Which method would work the easiest when the system was up as:

 $5x+3y=7$   $y=2x+1$  

• graphing

• elimination

• substitution

• none of these

 Solve by substitution
 $x+y=7$   $y=x+1$  

• (4, 5)

• (3, 4)

• no solution

• (6, 1)

Solve by elimination
 $3x-2y=1$  

 $2x+2y=4$  

• (1, 1)

• (5, 7)

• infinite solutions

• (-1, -2)

 Solve for Y ONLY by using elimination
 $x+2y=4$ 
 $-x-y=2$  

• y= 6

• y= 2

• y= -8

• y= -6

When solving by elimination, what would work to multiply and create opposites?
 $3x+2y=4$ 

 $-x-5y=2$  

• multiply the top by 2

• multiply the bottom by -2

• multiply the top by 3
  

• multiply the bottom by 3

is (-3, 2) a solution to the system:
 $x+y=-1$  
 $8-y=-2x$  

• yes

• no

• can't tell

If after solving, you end up with 5=5, that means

• no solution (false)

• x= 5

• infinite solutions (true)

• y= 5

 $-x+3y=5$  

 $y=3x-1$  

solve by substitution

• ( 1, 2)

•  $\left(\frac{4}{3},\ 3\right)$  

• (-1, -4)

 $-3x+12y=12$  

 $x=4y-4$  

Solve by substitution

• no solution

• infinitely many solutions