1. Do Now 10/4/11 In your notebook, answer the following question:
A cell phone bill is calculated using a two-step equation. Write a two-step equation for the following scenario. Your cell phone plan is $39.99 a month for 700 minutes and an additional $0.45 per minute for every minute over If your bill this month was $55.74, how many minutes did you talk in total for the month?
$0.45m + $39.99 = $55.74
= 735 minutes

2. Objective
3.3 solve multi-step equations using algebra

3. Equation- mathematical sentence with an equal sign Like a scale,
both sides must be
EQUAL in order
to be balanced.

4. Solving a Multi-Step Equation
How can you get the “unknown” by itself?
8x - 3x - 10 = 20
“Undo” operations by using the INVERSE (opposite) operation to both sides of the equation.
Solving Multi-Step Equations
STEP 1- Use Distributive Property
STEP 2- Combine like terms.
STEP 3- “Undo” addition and/or subtraction.
STEP 4- “Undo” multiplication and/or division.
STEP 5- Solve for the variable.
STEP 6- Check your work.

5. Solving Multi-Step Equations…
Isolate the variable! Get ‘x’ by itself.
8x – 3x – 10 = 20
5x – 10 = 20
Combine like terms.
5x – =
Add 10 to each side.
5x = 30
Simplify. = 30 5 5x
Divide each side by 5.
x = 6
Simplify.

6. 8x – 3x – 10 = 20 x = 6 8(6) – 3(6) – 10 = 20 Check Your Work!
8(6) – 3(6) – 10 = 20
Are both sides equal?

7. Solving Multi-Step Equations Using the Distributive Property…
Isolate the variable! Get ‘x’ by itself.
6x – 2(x – 5) = 46
6x – 2x + 10 = 46
Combine like terms.
4x + 10 = 46
Subtract 10 from each side.
4x + 10 – 10 = 46 – 10
Simplify.
4x = 36
Divide each side by 4. = 4x 4 36
Simplify.
x = 9

8. x = 9 6(9) – 2(9 – 5) = 46 Check Your Work! Are both sides equal?
6x – 2(x – 5) = 46
x = 9
6(9) – 2(9 – 5) = 46
Are both sides equal?

9. Guided Practice 2) p – 17p – 6 = -38 1) 6x – 2x + 11 = -5

10. Guided Practice 6x – 2(x + 11) = -6 6x + (-2x) + (-22) = -6

11. “Eric the Crane”
Eric the crane migrates from Canada to Texas. It takes Eric 14 days to travel 2500 miles. If Eric flies at an average speed of 25 miles per hour, how many hours of the migration is Eric NOT flying?
**HINT
Write an equation to see how long Eric is not flying.
Use ‘x’ to represent the amount of time Eric is not flying.
How many hours are there in 14 days?
Distance = Rate · Time spent flying
= · (336 – x)
= – 25x
236 hours = x