CHAPTER 11-6 SOLVING FOR A VARIABLE

OBJECTIVES

STUDENTS WILL BE ABLE: Solve a formula for a given variable.

Solve an equation in two or more variables for one of the variables.

1-6 SOLVING FOR A VARIABLE

What is solving for a variable? Answer: It means that we rearrange a

formula by inverse operations so we can isolate the requested variable.

What is a formula? Answer: formula is an equation that states a

rule for a relationship among quantities. An example of this can be: Athletes competing on racing. This athletes

can rearrange the distance formula(d=r*t) to find get the time it took to finish the race.

STEPS FOR SOLVING VARIABLES

Solving for a Variable Step 1 Locate the variable you are asked to

solve for in the equation. Step 2 Identify the operations on this

variable and the order in which they are applied.

Step 3 Use inverse operations to undo operations and isolate the variable.

EXAMPLE 1

Lets say the area of a rectangle is 45 meters and the length of the rectangle is 9 meters. What is the width of the rectangle?

Solution: First step is to get the formula and locate the

variable that you are asked to solve A is area, l is length and w is width Second step identify the operation on the

variable. Third step is to undo the operation with the

inverse and solve.

EXAMPLE 1 CONTINUE

Then we just substitute for the numbers.

EXAMPLE 2

Mrs. Smith is constructing a circular pool and wants to now the diameter of the pool. Given that the circumference of the pool is 30 mts.

Solution: formula for the circumference of a circle We need to divide by .

Now we substitute for the values given

EXAMPLE 3

A rectangular box has a volume of 365 cm cube. If the width of the box is 25cm and the length of the box 7 cm. What is the height of the box?

Solution:

EXAMPLE 4

Solve the following formulafor p:

Solution: locate p get rid of t first we solve for p

EXAMPLE 5

Solve the following formula for l:

Solution:

solve for l

EXAMPLE 6

Solve A = ( 1/2 )ah – ( 1/2 )bh for h Solution:

STUDENT GUIDE

Do odd problems 14-28 from page 52

HOMEWORK

Do even problems 14-28 from page 52

CLOSURE

Today we saw how to solve for a specific variable in an equation.

Tomorrow we are going to continue with 1-7