Solving Literal Equations

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Solving Literal Equations
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• Sometimes you have a formula and you need to
  solve for some variable other than the "standard"
  one.
• Example Perimeter of a square
• P4s
• It may be that you need to solve this equation
  for s, so you can plug in a perimeter and figure
  out the side length.

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• This process of solving a formula for a given
• variable is called "solving literal equations".

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• One of the dictionary definitions of "literal"
• is "related to or being comprised of letters.
• Variables are sometimes referred to as
• literals.

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• So "solving literal equations" may just be
• another way of saying "taking an equation
• with lots of variables, and solving for one
• variable in particular.

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• To solve literal equations, you do what
• you've done all along to solve equations,
• except that, due to all the variables, you
• won't necessarily be able to simplify your
• answers as much as you're used to doing.

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• Here's how "solving literal equations" works
• Suppose you wanted to take the formula for
• the perimeter of a square and solve it for s
• (or the side length) instead of using it to
• solve for perimeter.
• P4s
• How can you get the s on a side by itself?

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• P4s
• Just as when you were solving linear
• equations, you want to isolate the variable.
• So, what do you have to do to get rid of the
• 4?

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P4s

• Thats right, you have to divide by 4. You
• also have to remember to divide both sides
• by 4.

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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.
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• Lets look at another example
• 2Q-c d

Multiply both sides by 2.
      
Subtract c from each side.
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• As you can see, we sometimes must do
• more than one step in order to isolate the
• targeted variable.
• You just need to follow the same steps that
• you would use to solve any other Multi-Step
• Equation.

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Work these on your paper.

• 1. d rt for r
• 2. for w
• 3.

for t
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HW

• Pg. 148 2 to 20 even