Download 4.2 multistep equations

4.1 Multi Step Equations
So much fun!
Example of a multi step equation
• 4 – 3y = 4y + 10
• What do we do? Good question lets look
at the 3 steps…
The steps
1. Collect variable terms on one side of the
equation
2 Collect constant terms on the other side
of the equation
3 Solve for the variable
1. Collect variable terms on one
side of the equation
•
•
•
•
4 – 3y = 4y + 10
Lets subtract 4y from both sides
4-3y-4y = 4y + 10 -4y
4-7y=10
Step 2: Collect constant terms on
the other side of the equation
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•
•
•
•
4-7y=10
Lets subtract 4 from both sides
4-7y-4 = 10-4
-7y = 6
Y = -6/7
Step 3: Solve for the variable
• 7y = 6
• Y = 6/7
Another one to try
• 5x – 2 = 3x + 2
Here we go
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•
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•
5x – 2 = 3x + 2
5x-3x = 2+2 (two steps at same time…)
2x = 4
X=2
Hey Mr. Dearing, what if the
question has brackets in it?
•
Good questions follow these steps:
– Expand (get rid of brackets)
– Combine like terms
– Solve for the variable
Lets try it
•
•
•
•
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2(x + 1) + 3(2x – 1) = 0
2x + 2 + 6x – 3 = 0
2x + 6x = -2 + 3
8x = 1
X = 1/8
Another one! Woo whoo!
• -(x – 5) – 3(2x + 1) = 5
Lets do this!
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-(x – 5) – 3(2x + 1) = 5
-x + 5 - 6x – 3 = 5
-7x + 2 =5
-7x = 3
X = -3/7
Working by yourself.
• Try 1 a-c on your own
The triangle question.
• 2. The angles in a triangle add up to
______. Angle a is twice the size of angle
b. Angle c is triple the size of angle b.
Find the values of the three angles.
•
a
•
b
c
Lets break it down….
• If Angle a is twice the size of angle b then angle
a = 2b….
• If Angle c is triple the size of angle b then angle
c = 3b
• Angles of a triangle = 180 degrees
• A + b + c = 180
• 2b + b +3b = 180
• 6b=180
• B=30 degrees (therefore a = 60 and c= 90)