| For the first example, we will show you the Subtraction
Property of Equality. |
Example:
For any variables X, Y, or Z; if {X=Y}, then {X-Z = Y-Z} |
| Note that "Z" can be a negative or a positive number. | Example: | (1-Z = 1-Z)or (1-(+Z) = 1-(+Z) | (1-34=1-34)or (1-(+57)=1-(+57)) |
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| An Equation is almost like a scale. When you subtract something from one side, you have to
subtract it from the other side.
| Example: (8=8) If you subtract 1 from one side (8-1=8), then you must subtract 1 from the other side too. (8-1=8-1)=(7=7). |
Example 1 |
Solve (X+18= -7)(X+18=-7)Subtract 18 from each side.(X+18-18)=(-7)-18) )
(X+0=-25)(X=-25) |
Example 2 | Astronauts in
training have to lift weights in order to get in shape. Your pilot
lifted 150 at first when he started training. He worked toward a
goal of lifting 260 pounds. How many more pounds did he need to lift
to reach his goal?
Within the problem, find out what is being asked. Then define a variable for the equation. The answer to the problem is the amount of weight needed to reach the goal. |
Create an equation for the problem. Therefore, X = the amount of weight needed to reach the goal. |
Solve the Equation. The equation is 150 + X = 260: (X=110)Since your pilot already lifts 150 pounds and wants to lift 260 pounds, the answer is: 110 poundsSo, therefore, [(150 -150 + X= 260-150)], and [(X=260-150)].
The answer then would be: [(X=110)].
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