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Bell Ringer. Felicia ate one less than four times the number of cookies Araceli ate. If Felicia ate 11 cookies, how many cookies did Araceli eat? 4 a – 1 = 11 4a = 12 a = 3 cookies . 4a. – 1 . One less than twice Araceli. Twice Araceli. Homework. x = 4 x = 12 x = 1 x = 6
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Bell Ringer • Felicia ate one less than four times the number of cookies Araceli ate. If Felicia ate 11 cookies, how many cookies did Araceli eat? 4a – 1 = 11 4a = 12 a = 3 cookies 4a – 1 One less than twice Araceli Twice Araceli
Homework • x = 4 • x = 12 • x = 1 • x = 6 • x = 16/5 or 3 1/5 • x = -3 • x = -20.83 • x = .56 • x = 2 • x = 16 • x = 8 • x = 45/4 or 11 1/4 • X = 5 • X = 10 • X = 3.7 • X = 7.1 • X = -7 • X = 7 • X = -13 • X = -3 • X = 7.8
XEI 202: Solve equations in the form x + a = b, where a and b are whole numbers or decimals XEI 302: Solve one-step equations having integer or decimal answers XEI 403: Solve routine first-degree equations Solving One-Step Equationswith Multiplication and Division
Example: #1 In order to isolate “x”, we must get rid of the 3!!! 3x = 9 9/3 = 3, so x = 3! 3 3 x = 3 Golden Rule: If we divide one side by 3, we must divide the other side by 3! Check: 3 • 3 = 9 Yes!!!!
Example: #2 In order to isolate “x”, we must get rid of the -4!!! -4x = 20 20/-4 = -5, so x = -5! -4 -4 x = -5 We divide both sides by -4!!! Check: -4 • -5 = 20 Yes!!!!
Example: #3 1 x = 5 4 4 1 4 Multiply by the reciprocal! . Follow Golden Rule! . x = 5 4 1 1 5•4 x = 1 x = 20
Example: #4 Reciprocal Do the same!
Your Turn – Multiply & Divide • x = 7 • x = -5 • x = • x = 16 • x = 15 • x = 12 • 5x = 35 • -3x = 15 • -6x = 20 • ½ x = 8 • 2/5 x = 6 • ¼ x = 3
XEI 403: Solve routine first-degree equations XEI 404: Perform straightforward word-to-symbol translations XEI 501: Solve real-world problems using first-degree equations Two-Step Equations
Review… Multiplication & Division 6x = 18 6 6 x = 3 Addition & Subtraction x + 7 = 5 – 7 – 7 x = -2 -5 + x = 12 +5 +5 x = 17 2 5 x = 8 5 2 . 2 5 . 5 2 x = 8 x = 20
Two-Step Equations Step #1: Get rid of all addition and subtraction first! 2x + 9 = 15 To get rid of the +9, you would – 9 on both sides! – 9 – 9 2x = 6 2 2 Step #2: Get rid of all multiplication and division! To get rid of the 2, divide both sides by 2! x = 3 Check: 2(3) + 9 = 15 6 + 9 = 15 15 = 15
Two-Step Equations -5x – 7 = 13 Addition and Subtraction first! + 7 +7 -5x = 20 -5 -5 Multiplication and division second! x = -4 Check: -5(-4) – 7 = 13 20 – 7 = 13 13 = 13
Two-Step Equations 1 5 x + 2 = 8 – 2 – 2 1 5 . 5 1 5 1 . Multiply by the reciprocal! x = 6 x = 6•5 1 x = 30 Check: 1/5(30) + 2 = 8 6 + 2 = 8 8 = 8
Let’s Try These… 1. 5x – 9 = 11 2. -4x + 6 = 22 3. x + 5 = 20 4. x – 7 = 3 5x = 20 -4x = 16 x = 4 x = -4 3 4 1 6 1 6 3 4 x = 10 x = 15 x = 60 x = 20