2 Sometimes you have a formula and you need to solve for some variable other thanthe "standard" one.Example: Perimeter of a squareP=4sIt may be that you need to solve thisequation for s, so you can plug in aperimeter and figure out the side length.
3 This process of solving a formula for a given variable is called "solving literal equations".
4 One of the dictionary definitions of "literal" is "related to or being comprised of letters“.Variables are sometimes referred to asliterals.
5 So "solving literal equations" may just be another way of saying "taking an equationwith lots of variables, and solving for onevariable in particular.”
6 To solve literal equations, you do what you've done all along to solve equations,except that, due to all the variables, youwon't necessarily be able to simplify youranswers as much as you're used to doing.
7 Here's how "solving literal equations" works: Suppose you wanted to take the formula forthe perimeter of a square and solve it for ‘s’(or the side length) instead of using it tosolve for perimeter.P=4sHow can you get the ‘s’ on a side by itself?
8 P=4sJust as when you were solving linearequations, you want to isolate the variable.So, what do you have to do to get rid of the‘4’?
9 P=4s That’s right, you have to divide by ‘4’. You also have to remember to divide both sidesby 4.
10 This new formula allows us to use the perimeter formula to find the length of the sides of a square if we know the perimeter.
11 Let’s look at another example: 2Q-c = dMultiply both sides by 2.Subtract ‘c’ from each side.
12 As you can see, we sometimes must do more that one step in order to isolate thetargeted variable.You just need to follow the same steps thatyou would use to solve any other ‘Multi-StepEquation’.
13 Work these on your paper. 1. d = rt for ‘r’2. P = 2l +2w for ‘w’3.for ‘t’
14 Check your answers.1. d = rt for ‘r’2. P = 2l +2w for ‘w’3.for ‘t’