Join Karin Hutchinson for an indepth discussion in this video Solving subtraction equations using decimals, part of Learning Algebra: Solving Equations.
 Our last subtraction equation example…is going to involve decimals.…This equation, 5.8 = z  2.5, looks very confusing.…Not only does it have decimals,…but the problem is also written backwards.…There are actually two approaches…to solving this problem as well.…Some people don't mind working with the equation,…even though it's written backwards.…In that case, you would simply start…on the righthand side of the equation,…instead of the lefthand side.…
So, we could bring down z  2.5, and ask ourselves,…"What would we do to get rid of the  2.5?"…We need to get z by itself.…In order to get rid of  2.5,…we would use the opposite operation, which is to add 2.5.…Now, since I added 2.5 to the righthand side,…I now need to go back to the lefthand side,…and remember to add 2.5, as well.…
Now, on the lefthand side, I have 5.8 + 2.5,…that equals 3.3, and on the righthand side,…I'm left with just z, because 2.5 + 2.5 is 0,…and they cancel out.…So, my final answer is 3.3 = z,…and that is the correct answer,…even though it's written backwards.…
Author
Karin HutchinsonReleased
10/19/2015 Isolating variables
 Keeping equations balanced
 Solving addition and subtraction equations
 Solving multiplication and division equations
 Solving equations that involve the distributive property
 Solving twostep and multistep equations
 Solving equations with decimals and fractions
 Solving equations with variables on both sides
 Understanding literal equations
 Solving absolute value equations
Skill Level Appropriate for all
Duration
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Introduction

Welcome1m


1. Introduction to Solving Equations

Keeping equations balanced1m 30s

2. Addition Equations

3. Subtraction Equations

4. Multiplication Equations

5. Division Equations

6. TwoStep Equations

Solving a twostep equation1m 56s

7. Solving Multistep Equations with the Distributive Property

8. Solving Equations with Decimals

9. Solving Equations with Fractions

10. Solving Literal Equations

11. Equations with Variables on Both Sides

12. Solving Multistep Equations

13. Solving Absolute Value Equations

Conclusion

Next steps37s

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Video: Solving subtraction equations using decimals