6th Grade Math Textbook, Fundamentals

Lesson 13-6 for exercise sets. &KDSWHU 

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Graph each linear function. Then use the graph to findy whenx 4.

1.y x 2.y x  7 3.y  x 4.y x  10 5.y 2.5x

6.Discuss and Write Explain why only two points are needed to graph a

linear function.

1

2

The function y 10 x30 is a linear function. A is a

function whose graph is a nonvertical line. Any ordered pair on the

graph of a linear function is a solution of the related equation.

Refer to the graph on page 362. You can use the graph to find the total

cost of renting a car for any given number of hours.

Use the graph to determine how much it would cost

to rent a car for 3 hours.

To find the cost for 3 hours, find the point on the graph where x3.

From that point, move up to locate the corresponding y-coordinate, 60,

on the graph.

The cost of renting a car for 3 hours is $60, which is represented by the

ordered pair (3, 60).

The distance formula, drt, is an example of a linear function,

where d distance, r rate (or average speed), and ttime.

Omar rides his bicycle at an average speed of 8 miles per hour.

You can use a graphing calculator to show the relationship

between the time (how long Omar rides his bike) and the

distance he travels.

Press , and then enter the function d 8 t, or y 8 x.

Press , and select the scales and increments

for your graph.

Press to see the graph of the linear function.

Press to see specific ordered pair solutions.

You can type in a value for xand press. The calculator

will show you the corresponding y-value on the graph.

The entire graph shows all ordered pairs of the linear function d 8 t.

Use the graph to confirm that if Omar rides his bike for 8 hours

at a rate of 8 miles per hour, he will travel 64 miles.

linear function