DoNow WarmUp Exercises Plot the numbers on a

Do-Now Warm-Up Exercises Plot the numbers on a number line. 1. – 4, – 2, 1, 3 ANSWER 2. – 3, 0, 2, 5 ANSWER 3. 0. 4, 0. 9, 1. 3, 1. 6 ANSWER

Warm-Up 1 Exercises EXAMPLE Name points in a coordinate plane Give the coordinates of the point. a. A c. C e. E b. B d. D SOLUTION a. Point A is 3 units to the left of the origin and 4 units up. So, the xcoordinate is – 3, and the y-coordinate is 4. The coordinates are (– 3, 4). b. (2, – 3). c. (0, 2). d. (3, 1). e. (– 2, – 3).

Warm-Up 2 Exercises EXAMPLE Graph a function Graph the function y = 2 x – 1 with domain – 2, – 1, 0, 1, and 2. Then identify the range of the function. SOLUTION STEP 1 Make a table by substituting the domain values into the function.

Warm-Up 2 Exercises EXAMPLE Graph a function STEP 2 Graph the function. STEP 3 Identify the range. The range consists of the y-values from the table: – 5, – 3, – 1, 1, and 3.

Warm-Up 3 Exercises EXAMPLE Finding ordered pair solutions Which ordered pair is a solution of 3 x – y = 7? A (3, 4) B (1, – 4) C (5, – 3) D (– 1, – 2) SOLUTION Check whether each ordered pair is a solution of the equation. Test (3, 4): 3 x – y = 7 ? 3(3) – 4 = 7 5=7 ANSWER Write original equation. Substitute 3 for x and 4 for y. Simplify. The correct answer is B. A B C D

Warm-Up 4 Exercises EXAMPLE Graph an equation Graph the equation – 2 x + y = – 3. SOLUTION STEP 1 Solve the equation for y. – 2 x + y = – 3 y = 2 x – 3 STEP 2 Make a table by choosing a few values for x and then finding y. x – 2 – 1 0 1 2 y – 7 – 5 – 3 – 1 1 STEP 3 Plot the points. Notice that the points lie on a straight line. STEP 4 Connect the points by drawing a line through them. Use arrows to indicate that the graph goes on without end.

Warm-Up Exercises Word Problem GAS COSTS For gas that costs $2 per gallon, the equation C = 2 g gives the cost C (in dollars) of pumping g gallons of gas. You plan to pump $10 worth of gas. Graph the function and identify its domain and range. SOLUTION STEP 1 Identify whether the problem specifies the domain or the range. You know the amount of gas you plan to pump. Because cost is the dependent variable, the domain is specified in this problem. The domain of the function is 0 ≤ g ≤ 5.

Warm-Up Exercises GUIDED PRACTICE For the word problem STEP 2 Graph the function. Make a table of values. Then plot and connect the points. g(gas) 0 1 5 C(dollar) 0 2 10 STEP 3 Identify the unspecified domain or range. From the table or graph, you can see that the domain of the function is 0 ≤ C ≤ 10.