Solving Systems of Equations by Graphing and Substitution

Solving Systems of Equations by Graphing and Substitution

Poll

Would you rather be able to dodge anything no matter how fast it’s moving or be able to ask any three questions and have them answered accurately?

• Dodge

• Ask questions

Multiple Choice

y = 7 + 3x

What is the slope of this equation?

• 7

• 3

• 1/3

Multiple Choice

y = 7 + 3x

What is the y-intercept of this equation?

• 7

• 3

• 1/3

Open Ended

What is a system of equations?

Multiple Select

At how many points can 2 lines intersect? Check all the answers that are correct.

• 0 Points

• 1 Point

• 2 Points

• 3 Points

• All or infinite Points

Multiple Choice

If 2 equations have no intersection or no solutions it means that their lines are what?

• Skew

• Perpendicular

• Parallel

Multiple Choice

How many solutions are there for these two lines?

• 0

• 1

• 2

• infinite

Multiple Choice

How many solutions are there for these lines

• 0

• 1

• 2

• infinite

Multiple Choice

What is the solution or intersection point between these 2 lines?

• (2, -1)

• (2, 1)

• (-2, 1)

• (-2, -1)

Multiple Choice

What are the y-intercepts of the 2 lines, the points where they cross the y-axis?

• 1 AND 4

• -1 AND 4

• 4

• 1

Multiple Choice

What is the solution for these lines?

• ( 3, -2)

• (4 , 3)

• ( 4, -3)

Multiple Choice

Are these equations both solved for y?

• YES

• NO

Multiple Choice

Substitute what y equals in the second equation in for y in the first equation

• y = x - 9 -7x - 1

• y = -7x - 1 + x - 9

• x - 9 = -7x - 1

Multiple Choice

x - 9 = -7x - 1

Get the variable to one side by adding 7x to both sides

• 6x - 9 = -1

• 8x - 9 = -1

• -8x - 9 = -1

Fill in the Blank

8x - 9 = -1

Solve for x

Fill in the Blank

If x = 1

Plug that back into

y = x - 9 to find what y equals

Multiple Choice

Is the top equation or the bottom equation solved for y?

• Top equation

• Bottom Equation

• Neither

• Both

Multiple Choice

Substitute

y = -5x + 30

in to the second equation for y (using parentheses)

• 7x + 3y = -5x + 30

• -5x + 30 = 42

• 7x + 3(-5x + 30) = 42

Multiple Choice

7x + 3(-5x + 30) = 42

Distribute

• 10x - 5x + 30 = 42

• 7x - 8x + 33 = 42

• 7x - 15x + 90 = 42

Multiple Choice

7x - 15x + 90 = 42

Combine Like Terms

• -8x + 90 = 42

• 22x + 90 = 42

• x + 90 = 42

Fill in the Blank

-8x + 90 = 42

Solve for x

Fill in the Blank

If x = 6

Find what the y value is

by plugging into

y = -5x + 30

Multiple Choice

SO

x= 6

y = 0

What is the solution of the two equations

• (6, 0)

• (0, 6)

• (0, -6

Multiple Choice

After solving you are left with

-5 = 5

How many solutions are there to this problem?

• 0

• 1

• None

Poll

How well do you understand solving systems of equations?

• Completely understand

• Starting to get it

• Dont understand at all

Open Ended

You have an assignment on solving systems of equations-- You may pick any 7 of the 14 problems to solve. It is due next monday. When will you work on this assignment?