Solving Equations Using Addition & Subtraction
Objectives • Solve Equations by using addition & subtraction Notes 1. x + 5 = 12 What does it mean to “solve” an equation? • Find the value(s) of the variable that makes the equation true. • Get the variable all by itself on one side of the equation 3. x − 11 = 33 To solve equations, use inverse operations • Inverse operations “undo” each other. • Addition and Subtraction are inverse operations • Multiplication and Division are inverse operations The Big Rule of Algebra What you do to one side of an equation, you must do to the other side. 4. x − 4 = −9 2. x + 13 = 25 Examples Solve. Be sure to show all your work for full credit.
5. 21 = m − 12
6. −17 = x + 9
7. k + 11 = −21
8. n + ( −19 ) = −23
9. h − 26 = −29
10. r − 8 = −7
11. −33 = x − 12
12. r + 21 = −2
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Examples
13. p + 5 = −10
14. t + 13 = −14
15. x + 23 = −16
16. y − 5 = −8
17. y − 16 = −7
18. x − 190 = 215
19. m + 18 = −57
20. b + 15 = −32
Homework Solving Equations Using Addition & Subtraction
Solve each equation. Be sure to show your work for full credit. 2. x − 32 = −41 1. x + 5 = −13 4. 2.4 = m + 3.7 3. x − 12 = −36 5. k − 7 = −16 6. x + ( −1.4 ) = 0 7. g + ( −8 ) = 7 9. −23 = m − 19 11. x − 6.5 = −9.3 13. w + ( −1.43) = 0.89 15. −4.1 = m + ( −0.5 ) 8. h − 26 = −29 10. −11 = y + ( −5) 12. m − ( −16 ) = 9 14. m − ( −13) = 37
21. k + 9 = −53
22. x − ( −4 ) = −15
5 5 16. x − = 8 8 3 5 2 1 17. x − = 18. y + − = − 10 6 3 5 19. Find the square root of 256. Simplify 20. 65 ÷ ( −13) 21. −0.23x + ( −0.5 x )
22. 6 ( 5a + 3b − 2b )
23. 12 ÷ 4 + 15 ⋅ 3