Bell Work 1.Label the quadrants 2.Plot the points A(-2,1), B(4,1), C(4,-3), and D(-2,-3) 3. Find the area and perimeter of the figure Q1 Q4Q3 Q2 A(-2,1) D(-2,-3) C(4,-3) B(4,1) Area = 4 × 6 =24 units 2 Perimeter = = 20 units

Skills Check! When you finish turn your paper over and put it in the corner of your desk. Silent read or work on other homework. No talking.

Evaluating a Function Evaluate the function y = 5x when x = 7. y = 5x = 5(7) Substitute 7 for x. = 35 Multiply.

Evaluating a Function Fundraising Your soccer team is selling glow sticks to raise money. The team paid $50 for a case of 48 glow sticks and sells each glow stick for $3. How many glow sticks does the team need to sell to start earning a profit? Use the function rule P = 3g – 50, where P is the profit in dollars and g is the number of glow sticks your team sells. SOLUTION Make a table to determine how many glow sticks your soccer team needs to sell to start earning a profit.

ANSWER Your soccer team needs to sell 17 glow sticks. Evaluating a Function

KEY TERMS Function – a relationship where one thing depends on another Function Table – a way to organize the input numbers, output numbers, and the function rule Domain – set of input values (x) Range – set of output values (y) Linear Equation – graph of a straight line Ordered Pair – a pair of numbers used to locate a point in a coordinate system

Make a Function Table Your test grades for the semester are a 95%, 80%, 63%, 97%, 95% InputOutput DomainRange 95% 63% 80% 97% A B A D 95% A

Make a Function Table Suppose you earn $5 each week. Make a function table that shows your total earnings after 1, 2, 3, and 4 weeks. Input (x) Function Table Output (y) # of wksy=5xtotal DomainRange (1) 5 (2) 5 (4) 5(3)

Sometimes we use “function machines” to determine rules of functions. Practice using a Function The rule of the function Input Output

Input-Output Machines We can think of equations as input-output machines. The x- values being the “inputs” and the y-values being the “outputs.” Choosing any value for input and plugging it into the equation, we solve for the output. y = -2x + 5 y = -2(4) + 5 y = y = -3 x = 4 y = -3

Function Tables In (x)Out (y) The input is a number going in. Let’s imagine this equation y = x+ 5 The output is the result of applying the rule ( + 5) + 5 is the rule

Function Tables In (x)Out (y) – 23 – The input is a number going in. Let’s imagine this equation y = x+ 5 The output is the result of applying the rule ( + 5) + 5 is the rule

Making an Input-Output Table horizontally Make an input-output table for the function y = x – 1.3 using the domain 0, 1, 2, and 3. Then state the range of the function. SOLUTION The range of the function is the set of outputs –1.3,– 0.3, 0.7, and 1.7.

You try: 1.Make an input-output table for the function y = 2x + 2 using the domain –2, – 1, 0, 1, and 2. Then state the range of the function. Input x –2–1012 Substitution y = 2(-2) + 2y = 2(-1) + 2y = 2(0) + 2y = 2(1) + 2y = 2(2) + 2 Output y SOLUTION The range of the function is the set of outputs –2, 0, 2, and 6.

Function Tables InOut Find the pattern and fill in the numbers then write the function rule. Function rule: y= x

Function Tables InOut Function rule: y = 3x Find the pattern and fill in the numbers then write the function rule.

Function Tables InOut Function Rule: y= x – 6 Find the pattern and fill in the numbers then write the function rule.

Function Tables InOut Function rule: y = x ÷ 4 Find the pattern and fill in the numbers then write the function rule.

Function Tables InOut Function rule: y = x + 13 Find the pattern and fill in the numbers then write the function rule.

Practice: Worksheet