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WARM UP. 3. Solve the equation 4x + 8 = 24 3x – 5x = -12 3x + 9 = 9x - 7. WARM UP. 2. Solve the equation x + 6 = 14 9 – y = 4 4x + 5y =15. WARM UP. 1. Solve the equation x + 6 = 14 9 – y = 4 4x + 5y =15. WARM UP. 0. Solve the equation x + 6 = 14 9 – y = 4 4x + 5y =15.
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WARM UP 3 Solve the equation 4x + 8 = 24 3x – 5x = -12 3x + 9 = 9x - 7
WARM UP 2 Solve the equation x + 6 = 14 9 – y = 4 4x + 5y =15
WARM UP 1 Solve the equation x + 6 = 14 9 – y = 4 4x + 5y =15
WARM UP 0 Solve the equation x + 6 = 14 9 – y = 4 4x + 5y =15
4.8 Functions and Relations Today’s Schedule: Lesson 4.8 Powerpoint In class assignment/homework Exit Slip GOAL: Decide whether a relation is a function and use function notation. KEY WORDS: relation, function, vertical line test, function notation, linear function.
4.8 Functions and Relations FUNCTION NOTATION When a function is defined by an equation, it is often convenient to name the function. Just as x is commonly used as a variable, the letter f is commonly used to name a function. To write a function using FUNCTION NOTATION, you use f(x) in place of y. x-y notation: y = 3x + 2 function notation: f(x) = 3x + 2
4.8 Functions and Relations SOLUTION You can evaluate a function for a given value by substituting the iven value for the variable and simplifying. EXAMPLE 3: Evaluate a Function Evaluatef(x) = 2x -3 when x = -2 • Write the original function. • Substitute -2 for x. • Simplify.
4.8 Functions and Relations a. Evaluate f(x) = 4x + 5 when x = 2 b. Evaluate g(x) = x2when x = 3 CHECKPOINT: Evaluate a Function
4.8 Functions and Relations LINEAR FUNCTION A function is called a linear function if it is of the form f(x) = mx + b. For instance, the function in Example 3 part a is linear. But, the function in Example 3 part b is not linear. To graph a linear function, rewrite the function using x-y notation.
4.8 Functions and Relations SOLUTION • Rewrite the function in x-y notation. • Find the slope and the y-intercept • Use slope to find a second point • Draw a line through the two points EXAMPLE 4: Graph a Linear Function Graphf(x) = -2x + 3