Test 5A Preview Solving system of equations

Using the ELIMINATION method, what are the 1st and 2nd steps if you wanted to eliminate the y  variable in this system?

-4x + 9y = 9

 x - 3y = -6

• Multiply the bottom equation by 3; then Add the equations together, thus eliminating y

• Add 4 to the bottom equation; then Add the equations thus eliminating x

• Add 6y to the bottom equation; then Subtract the equations, thus eliminating y 

Solve the system using the SUBSTITUTION METHOD:

y = -2

4x - 3y = 18

What does x = ?

What is the first step in solving this system by ELIMINATION if we want to eliminate the x variable first?

5x + y = 9

10x - 7y = -18

• Multiply entire top equation by 2

• Add both equations together

• Subtract the bottom equation from the top

• Divide the bottom equation by 7

Solve the system by substitution.

y= -5

5x + 4y = -20

x=?

• 0

• -5

• 1

• -2

What is the solution to this system. (See graph)

y = -2x + 2

y = -2x - 2

• No solution - Perpendicular lines

• No Solution - Parallel lines

• Infinite solutions - Coincident lines

• just 1 solution (0,-2)

• 2 solutions (0, .25) and (.25, 0)

• No solutions

• Coincident lines - infinite solutions

• 1 solution - at (0, .25)

Solve using elimination.  Which one of these is a TRUE 1st step?

-3x-2y=-12
3x+8y=-24

• add equations together to eliminate x

• subtract equations to eliminate y

• multiply top equation by 4 to eliminate x

• divide bottom equation by 3 to eliminate y

When graphing a system of equations what are the possible outcomes?

• intersecting, parallel, and same (coincident) lines

• only intersecting and parallel lines

• only perpendicular and parallel lines

• insects, parsecs, and similar lines

What is the solution to the graphed system of equations?

Must type in (x,y) format

(what is the x and y?)

Which of the following is a valid first step to solve the system using elimination?

2x + 3y = 6

4x - y = 8

• Add the equations together

• Subtract the second equation from the first

• Multiply the top equation by 2

• Divide the second equation by 2