Solving Written Problems

SEI.3.AC.1SLE 1: Solve, with and without appropriate technology, multi-step equations and inequalities with

rational coefficients numerically, algebraically and graphically

Students will be able to write the equations to solve problems.

Equations and Inequalities 2FHS

Simple Problems

• Multiply a number by 3 and you get 15. Find the number.

• What will our variable represent?

• Let’s translate into symbols the sentence

“Multiply by 3a number and you get 15.”

a number

x3· = 15

Equations and Inequalities 3FHS

Equal sign?

• What words or phrases would mean equal?• Here are some examples

equals

is equal to

is or are

was or were

will be

and you get

Equations and Inequalities 4FHS

Example 1

Solve this problem: In 5 years, Linda will be 20 years old. How old is she now?

• What will our variable represent?

Linda’s age now• How old will Linda be in 5 years

x + 5• So now our equation would be:

x + 5 = 20

Equations and Inequalities 5FHS

Diane drove 240 miles in 4 hours. What is her rate of speed?

• What will our variable represent?

Her rate of speed• What formula should we use to set up the

equation?

rate x time = distance• What is the equation?

4 · x = 240

Examples 2

Equations and Inequalities 6FHS

Two more than 3 times a number is 4 less than 2 times the number.

• What would be the variable? Where will the = go?

the number• Translate “2 more than 3 times a number”

3x + 2• Translate “4 less than 2 times the number”

2x – 4 • What is the equation?

3x + 2 = 2x - 4

Examples 3