LESSON - Solve by Multiplying
- Instruct that minus and negative are equivalent
GOAL-to isolated the specified variable
- Instruct that what is done on one side of the equation (= sign), must be done on the other side of the = sign.
I a. Problem: 2/3x = 5
Step 1: Identify the variable we are solving for: (x)
Step 2: To isolate that variable, you must multiply both sides by the reciprocal of 2/3, which is 3/2.
(3/2) (2/3)x = 5 (3/2)
Step 3: Multiply and simplify if necessary
1x = 5/1 * 3/2
x = 15/2
Note: You may leave the answer as an improper fraction or you can change it to a mixed number.
I b. Problem: 2/3x = 5 (Another option to solving this problem, especially for students who have difficulty with fractions). This combines multiplication and division.
Step 1: Same as above
Step 2: Multiply both sides by the denominator, this leaves you with just the numerator.
(3) 2/3x = 5 (3)
Step 3: Multiply: 2x = 15
Step 4: Divide both sides by the coefficient (2)
2x/2 = 15/2
Step 5: Simplify: x = 15/2