1. An equation remains true when both sides are operated on in the same way:
= 3
+ 4
+ 4
7 = 7
Be careful:
1 + 2 x 4 = 3 x 4
Is NOT TRUE
= 3
- 4
- 4
-1 = -1
( ) = 3
x 4
x 4
12 = 12
But:
1 x x 4 = 3 x 4
Is TRUE
( ) = 3 4 4
0.75 = 0.75
Designed by Lukas van Veen

2. n + 3 = 7 4 Guess n + 3 = 7 + 3 n + 3 = 7 - 3 - 3 n + 0 = 4 n = 4
Find n in the following equation :
n = 7 4
Guess
How do I find the answer using algebra?
n = 7
+ 3
I want an answer in the form
n = ….
n = 7
I must remove +3
n = 4
n = 4

3. There is a quicker way to solve the same equation :
= 3
- 2
Move + 2 to the other side and change its sign
n = 7
- 3
Move + 3 to the other side and change its sign
n = 4
Designed by Lukas van Veen

4. Solve the following equations :
Move – 0.75 to the other side and change its sign
m = 0.875
+ 0.75
m = 1.625
Move – 4.7 to the other side and change its sign
- 4.7 – h = 7.8
+ 4.7
– h =
Beware:
I want h,
NOT -h
– h = -
Change
ALL signs
Designed by Lukas van Veen

5. 4 n = 12 4 4 n = 3 x 3 x 3 Solve the equation 4n = 12
Remove 4 by dividing both sides by 4
4 n = 12 4 4
n = 3
Solve the equation
Remove 3 by multiplying both sides by 3
x 3
x 3
Designed by Lukas van Veen

6. Solve the equation 2n + 5 = 11
Move 5 to the other side and change its sign
Remove 2 by dividing both sides by 2
2 n = 11
- 5
2 n = 6 2 2
Solve the equation
n = 3
- 4
- 3
- 3
m =
Designed by Lukas van Veen