HW 2 2 Worksheet Please take out your completed Section 2 2 homework worksheet now and pass it to the end of your table nearest the center of the room so the TA can pick them up Late papers won t be accepted A new worksheet will be handed out now for HW 2 3 due tomorrow Reminder The next homework assignment on section 2 3 is due at the start of next class period Make sure you turn in the worksheet showing all your work for problems 11 22 of this assignment If you don t turn this in or if you don t completely show your work on any problem s your online score will be reduced for those problems The good news No more worksheets for a week or so Any questions on Section 2 2 Explore the online Gradebook function 1 Click the Gradebook menu button 2 Select Homework in Assignments heading at top Go to desired HW section select Review You can actually work or rework problems after the deadline has passed e g to study for quiz like the one that s coming up in a few days but it won t change your grade Now please CLOSE YOUR LAPTOPS and turn off and put away your cell phones Sample Problems Page Link Dr Bruce Johnston Section 2 3 Formulas Problem Solving Formula A formula is an equation that states a known relationship among multiple quantities has more than one variable in it Examples of Formulas A lw I PRT Area of a rectangle length width Simple Interest Principal Rate Time P a b c d rt NOTE You DO NOT have to memorize these formulas You DO have to know how to use them Perimeter of a triangle side a side b side c distance rate time V lwh Volume of a rectangular solid length width height C 2 r Circumference of a circle 2 radius Example A flower bed is in the shape of a triangle with one side twice the length of the shortest side and the third side is 30 feet more than the length of the shortest side Find the dimensions if the perimeter is 102 feet Relevant formula P a b c Perimeter of a triangle side a side b side c Understand and Translate Read and reread the problem If we let x the length of the shortest side x then 2x the length of the second side and x 30 the length of the third side x 30 Perimeter sum of all the sides x 2 x x 30 So x 2 x x 30 102 2x Example cont Solve 102 x 2x x 30 102 4x 30 simplify right side 102 30 4x 30 30 subtract 30 from both sides 72 4x simplify both sides 72 4 x 4 4 divide both sides by 4 18 x simplify both sides Example cont Interpret Check If the shortest side of the triangle is 18 feet then the second side is 2 18 36 feet and the third side is 18 30 48 feet This gives a perimeter of P 18 36 48 102 feet the correct perimeter State The three sides of the triangle have a length of 18 feet 36 feet and 48 feet It is often necessary to rewrite a formula so that it is solved for one of the variables This is accomplished by isolating the designated variable on one side of the equal sign Steps for Solving Formulas 1 Multiply to clear fractions 2 Use distributive property to remove grouping symbols parentheses and brackets 3 Combine like terms to simply each side 4 Get all terms containing specified variable on the same side other terms on opposite side 5 Isolate the specified variable using the distributive property in reverse 6 Divide both sides by the quantity that s now in front of the variable you re solving for Many times this will be an expression in parentheses but not always T mnr T mnr mr mr T n mr divide both sides by mr simplify right side Example 2 Solve the formula for T A P PRT A P P P PRT Subtract P from both sides Simplify right side A P PRT A P PRT Divide both sides by PR PR PR A P Simplify right side T PR Example 3 Solve the formula for P A P PRT A P 1 RT A P 1 RT 1 RT 1 RT A P 1 RT Isolate P by factoring out P from both terms on the right side Divide both sides by 1 RT Simplify the right side Example 4 Solve for v T 3vs 4ws 5vw Get rid of terms on right that don t have a v i e add 4ws to both sides T 4ws 3vs 5vw Isolate the v on the right by factoring it out of both terms T 4ws v 3s 5w Divide both sides by the part in parentheses T 4ws v 3s 5w 3s 5w 3s 5w Simplify by canceling the common part on the right T 4ws v DONE 3s 5w Example from today s homework Answer T 5C or T 5 BC BC B 2 3 HW NOTE Dealing with negatives in the denominator EXAMPLE Solve 6x 7y 15 for y 1 Subtract 6x from both sides 7y 15 6x 2 Divide both sides by 7 y 15 6x 7 3 This is the answer but not in simplified form We must multiply the top and bottom by 1 to make the denominator positive 4 y 1 15 6x 15 6x 6x 15 1 7 7 7 Word problem from today s homework Answer 2940 22 Remember to show work on worksheet for problems 11 22 Show steps similar to those shown as it s worked on the whiteboard in class Reminder This homework assignment on section 2 3 is due at the start of next class period Make sure you turn in the worksheet showing all your work If you don t complete this and turn it in your online score will be reduced You may now OPEN your LAPTOPS and begin working on the homework assignment