Write the equation of the line…

Write the equation of the line…

Through (4, 5) and (6, 9)

Write the equation of the line…

Write the equation of the line…

Solve by Graphing

Section 3.1

According to one plan, the repair cost is $50 plus $10per hour. Another plan is $75 plus $5 per hour. Which plan should I choose? When are they the same?

System of Equations

Consists of 2 or more equations with 2 or more variables

Solution

A point (x, y) is said to be a solution to a system of equations if it satisfies both equations.

Given:

Is (9, 5 ) a solution?

Is (7, 3) a solution?

6 9 15

4

x y

x y

Definitions

Consistent – has at least one solution Dependent – Infinite number of solutions Independent – has exactly one solution

Inconsistent – has no solution

Consistent

Independent

Consistent

Dependent Inconsistent

Solve by graphing:

3 2

3 4

y x

x y

Solve by graphing:

4 20

6 4 8

x y

x y

Solve by graphing:

4 3 9

8 6 12

x y

x y

To Solve with the calculator:

First Solve each equation for y Press y= and put the first equation into y1

and the 2nd equation into y2 Press 2nd TRACE - #5 intersect

Solve w/Calculator:

3 2

9 3 6

y x

x y

Solve w/Calculator:

Solve w/Calculator:

Solve w/Calculator:

Solve w/Calculator:

Homework

Worksheet