1. Do Now 10/22/13 + 7 = 10 = ? Copy HW in your planner.
Text p. 74, #1-3, 8-13, 38, 39, & 41
In your journal, describe the PROCESS (steps you would take) to solve the following question. Then solve. What is this an example of?
+ 7 = 10
= ?

2. Objective
SWBAT solve equations using addition and subtraction

3. Section 2-5 “Solving Equations Using Addition & Subtraction”
mathematical sentence formed by placing an “=” between two expressions
y – 8 = 12
22 = 14 + z
5 ÷ x = 30
11a = 121

4. Equation x
+ 7 = 10
Left side
Right side
‘x’ has to be 3 in order to make the equation balanced.
Like a scale, the left side and right side must be the same in order to be balanced!

5. How can you get the “unknown” by itself?
m + 24 = -18
“Undo” the operation by using the INVERSE (opposite) operation to both sides of the equation.

6. Solving Addition Equations…
Isolate the variable! Get ‘m’ by itself.
m + 24 = -18
To get the ‘m’
by itself get rid of
“adding 24.”
–24
– 24
Do the opposite.
“Subtract 24.”
m = -42
Whatever you do to
one side of the equation
you must do the other side.
-18 – 24
-18 + (-24) “opp-opp”
-42

7. m = -42 m + 24 = -18 (-42) + 24 = -18 -18 = -18 Check Your Work!
-18 = -18
Are both sides equal?

8. Try It Out 1). (6) + 7 = 13 1). x + 7 = 13 2). -7 = 9 + (-16)
1). (6) + 7 = 13
2). -7 = 9 + (-16)
3). -3 = (-10) + 7
4).(-9) + 40 = 31
1). x + 7 = 13
2). -7 = 9 + h
3). -3 = x + 7
4). f = 31

9. Solving Subtraction Equations…
Isolate the variable! Get ‘y’ by itself.
-13 = y –15
To get the ‘y’
by itself get rid of
“subtracting 15.”
+15
+15
Do the opposite.
“Add 15.”
2 = y
Whatever you do to
one side of the equation
you must do the other side.

10. 2 = y -13 = y – 15 -13 = (2) – 15 -13 = -13 Check Your Work!
Are both sides equal?

11. Try It Out 1). (4) - 7 = -3 1). t - 7 = -3 2). 6 = (3) – (-3)
3). 40 = (61) – 21
4). -15 = (-8) - 7
1). t - 7 = -3
2). 6 = x – (-3)
3). 40 = r – 21
4) = p - 7

12. 24
Homework
Text p. 74, #1-3, 8-13, 38, 39, & 41