In a formula like that for speed we can say that speed is the subject of the equation because the formula tells us what speed is. We can rearrange or manipulate the formula so that either distance or time is the subject of the equation. See image below.
Instead of asking you to make distance the subject of the equation you may be asked to express distance in terms of speed and time. In the Khan Academy videos they say solve for distance. These all mean the same thing.
These videos and exercises are quite short and are worth working your way through them.
Remember:
- Anything you do to one side of an equation you must do to the other.
- Be able to identify how many terms an equation has.
- When multiplying or dividing an equation each term must be multiplied or divided.
- If the letter that you are looking for is in more than one term then you need to bring these terms together and then factorise.
- In the video Sal says "cancelling" - What he means is "divides into once".
There are some more examples done as a pencast below.
_
0 comments:
Post a Comment