1. 3rd High school in Kalamaria Second class
Lesson plan:
SOLVING TWO - STEP EQUATIONS
using an interactive whiteboard
Teacher of the course: Kalaitzi Anna

2. Solving a two-step equation
Put the reasons in the right order
reasons
Steps
Subtraction property of equality
8-3y=14
8-3y-8=14-8
Division property of equality
-3y=6
simplify
simplify
y= -2
Original equation

3. Solving a two step equation
Put the steps in the right order
reasons
Steps
12-2a=8
Original equation
a= 2
Subtraction property of equality
simplify
-2a=-4
Division property of equality
12-2a-12=8-12
simplify

4. Solving a two step equation
Justify each step
Steps
reasons
-x-5=11
-x-5+5=11+5
-x=16
x=-16

5. Find the error? Steps 12-3y= 15 Original equation 12-3y-12=15-12 3y=3
reasons
12-3y= 15
Original equation
12-3y-12=15-12
Subtraction property of equality
3y=3
simplify
Division property of equality
y= 1
simplify

6. Find the error? Steps Original equation simplify
reasons
Original equation
Subtraction property of equality
simplify
Multiplication property of equality
simplify
m= -4

7. Define a variable and write an equation for this situation. Then solve.
Beneath Earth’s surface, the temperature increases 10˚C every kilometer. Suppose that the surface temperature is 22˚C, and the temperature at the bottom of a coal mine is 45˚C. Which equation could be used to find the depth d of the coal mine?
Depth of a coal mine in kilometer d
Temperature increases at d kilometer
10d
Temperature at the bottom of a coal mine 22
The surface temperature 45

8. Put at the write position:
Beneath Earth’s surface, the temperature increases 10˚C every kilometer. Suppose that the surface temperature is 22˚C, and the temperature at the bottom of a coal mine is 45˚C. Which equation could be used to find the depth d of the coal mine?
number of kilome-
ters
the depth of the coal mine
Surface tempe-
rature
Tempe-
rature increase
plus
times
equals
Put at the write position: d = 45 22 10 * +

9. Now solve the equation!

10. Time for fun

13. Thank you!