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3.7 Formulas and Functions. Goal 1: Solving Formulas. Goal 2: Rewrite an equation in function form. Formula – an algebraic equation that relates two or more real-life quantities. Use this given formula to solve the first example: A = lw Example 1: Find a formula for w, in terms of A and l.
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3.7 Formulas and Functions Goal 1: Solving Formulas. Goal 2: Rewrite an equation in function form.
Formula – an algebraic equation that relates two or more real-life quantities. • Use this given formula to solve the first example: A = lw • Example 1: Find a formula for w, in terms of A and l. • Step 1: Manipulate the equation and solve for w. • w = A/l
Example 2 • C=(5/9)(F-32) is the temperature formula. • Solve for F. • . • . • . • (9/5)C + 32 = F
Example 3 • I = Prt where I is the interest earned, P is the amount of dollars we started with, r is the rate, and t is the time. • Solve for t. • Find the number of years t that $2800 was invested to earn $504 at 4.5%. • 4 Years
HW#1 • Pg 177 (15-29all)
Example 4 • d = rt • The space probe named Algebra Voyager III traveled from Earth to Mars in 212 days. It traveled 310 million miles. • Estimate how long it would have taken to reach Mars at the following speeds. • a) 30,000 • b) 60,000 • c) 80,000 • Which of the 3 speeds is the best to estimate the Algebra Voyager III average speed?
Rewriting equation in function form • Function form – when a two variable equation is arranged so that one of the variables is isolated on one side of the equation. • The isolated variable then becomes the output and is a function of the input.
Ex. 4: Rewrite the equation 3x+y=4 so that y is a function of x. • y=4-3x • No rewrite the equation so that x is a function of y. • Use the results to find x when y=-2, -1, 0, and 1. Put into and input-output table.
HW#2 • Pg. 177-179 ( 30-34 all, 40, 45, 46, 50-58all)