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You are trying to find the value of x which makes this equation true (equal). How can you do this? 4x + 12 = 15 make both sides zero get x alone get 12 alone How would you get x alone? You need to get x alone on one side of the equal sign. 4x + 12 = 15 use inverse (opposite) operations multiply by zero add x to each term Use inverse (opposite) operations to get x alone. Which numbers need to be cancelled out to get x alone? 4x + 12 = 15 4 and 15 4 and 12 12 and 15 The term farthest from x needs to be cancelled out first. 4 and 12 need to be cancelled out to get x alone. 4x + 12 = 15 Which term is farthest from x? 12 4 What would you do to BOTH sides of the equation to cancel out +12 ? 4x + 12 = 15 add 12 multiply 12 divide 12 subtract 12 Subtract 12 from both sides. What will the equation look like now? 4x + 12 = 15 - 12 4x = 27 4x + 24 = 3 4x = 3 - 12 What would you cancel next to get x alone? 4x + 12 = 15 3 4x = 3 - 12 OR - 12 4 * Cancel out the 4 to get x alone What would you do to BOTH sides of the equation to cancel out 4 (times four)? 4x = 3 add 4 multiply 4 divide 4 subtract 4 What does x equal? 4x = 3 4 4 4/3 -1 3/4 12 x = 3/4 4x = 3 4 4 Plug in (substitute) 3/4 for x to check your solution. (the equation will be equal if 3/4 is correct) √ 4 +12 = 15 4 + 12 = 15 (¾) x Your solution What number is three-fourths of four +12 = 15 4 +12 = 15 4 + 12 = 15 (¾) x ? Since x = ¾ makes the equation equal (15 =15), x = ¾ is the correct answer. 3 + 12 = 15 15 = 15 √ The n d |