3.5  Solving Equations That Involve Decimals

Mrs. Agriesti's Algebra

Goal:  To learn techniques to solve equations with decimals.

• To clear an equation of decimals, multiply each term by the same multiple of ten (10, 100, 1000, …).
  

• To clear an equation of fractions, multiply each term by the least common denominator.  (Section 11.8).
  

Example 1:

Add 35 to each side.


Divide by 47 on each side.

Use a calculator.  Round to two decimal places.

Example 2:

Subtract 47 from each side.


Divide by -17 on each side.

Use a calculator.  Round to two decimal places.

Example 3:

Multiply each term by 100.

Subtract 46 and add 3819 to each side.


Divide by 1914 on each side.

Use a calculator.  Round to two decimal places.

Example 4:

Multiply each term by 100.

Add 250x and subtract 1257 on each side.

Divide by -173 on each side.
Use a calculator.  Round to two decimal places.

Example 5:

Multiply each term by the least common denominator, 12.


Simplify
Subtract 6x and subtract 9 from each side.



Divide by 18 on each side.