This method can be used to equations. When using this method it may help to keep the sign lined up so that you can see when something moves from one side to the “=” other. Examples: Solve the equation: 5b + 8 = 23 (collect b’s at one side, numbers at the other.) 5b + 8 = 23 Starting Equation. 5b = 23 - 8 +8 crosses the sign and becomes -8. “=” 5b = 15 Tidy up. b = 15 ÷ 5 X5 crosses the sign and becomes ÷5. “=” b = 3 Final answer Solve the equation: 7t + 4 = 3t - 12 (collect t’s at one side, numbers at the other.) 7t + 4 = 3t - 12 Starting Equation. 7t = 3t - 12 - 4 +4 crosses the sign and becomes -4. “=” 7t = 3t - 16 Tidy up. 7t 3t = -16 +3t crosses the sign and becomes -3t. – “=” 4t = -16 Tidy up. t = -16 ÷ 4 X4 crosses the sign and becomes ÷4. “=” t = - 4 answer Solve: 3(2a 4) = 2(a + 8) (collect a’s at one side, numbers at the other.) – 3(2a - 4) = 2(a + 8) Starting Equation. 6a - 12 = 2a + 16 Multiply out brackets (to separate a’s and numbers) 6a = 2a + 16 + 12 -12 crosses the sign and becomes +12. “=” 6a = 2a + 28 Tidy up. 6a 2a = 28 +2a crosses the sign and becomes -2a. – “=” 4a = 28 Tidy up. a = 28 ÷ 4 X4 crosses the sign and becomes ÷4. “=” a = 7 Final answer
This method can be used to equations. When using this method it may help to keep the “=” sign lined up so that you can see when something moves from one side to the other. Examples: Solve the equation: 5b + 8 = 23 (collect b’s at one side, numbers at the other.) Starting Equation. 5b + 8 = 23 +8 crosses the “=” sign and becomes -8. 5b = 23 - 8 Tidy up. 5b = 15 X5 crosses the “=” sign and becomes ÷5. b = 15 ÷ 5 Final answer b = 3 Solve the equation: 7t + 4 = 3t - 12 (collect t’s at one side, numbers at the other.) Starting Equation. 7t + 4 = 3t - 12 +4 crosses the “=” sign and becomes -4. 7t = 3t - 12 - 4 Tidy up. 7t = 3t - 16 +3t crosses the “=” sign and becomes -3t. 7t – 3t = -16 Tidy up. 4t = -16 X4 crosses the “=” sign and becomes ÷4. t = -16 ÷ 4 answer t = - 4 Solve: 3(2a – 4) = 2(a + 8) (collect a’s at one side, numbers at the other.) Starting Equation. 3(2a - 4) = 2(a + 8) Multiply out brackets (to separate a’s and numbers) 6a - 12 = 2a + 16 -12 crosses the “=” sign and becomes +12. 6a = 2a + 16 + 12 Tidy up. 6a = 2a + 28 +2a crosses the “=” sign and becomes -2a. 6a – 2a = 28 Tidy up. 4a = 28 X4 crosses the “=” sign and becomes ÷4. a = 28 ÷ 4 Final answer a = 7