Solving Equations and Checking
Solve one-variable linear equations with natural number solutions; verify the solution by substitution.
Solving means getting the letter alone. Whatever you do to one side you must do to the other, and then you check by putting your answer back in.
Method
Do the same to both sides
That is the only rule. Everything else follows from it.
Undo with the opposite operation
Work backwards through what was done to the letter.
Always verify by substitution
It costs ten seconds and catches every arithmetic slip.
Worked example
e.g.
- Look at what has been done to : multiplied by 4, then 5 added.
- Undo the last step first. Subtract 5 from both sides.
- Simplify.
- Undo the multiplication. Divide both sides by 4.
- Verify by substituting back into the original equation.
Practice
Solve, then verify by substitution.
1
Answer
2
Answer
3
Answer
4
Answer
5
Answer