Solve the Equation :
n-3 = n+6
2
3
We cannot solve this Equation using “Onion
Skins” or “Back-Tracking”, because our
Equation has Fractions and the Variable
letter “n” is on both sides of the Equation.
WE NEED TO DO SOME EXTRA STEPS
BEFORE WE CAN SOLVE THE EQUATION
Solve the Equation :
n-3 = n+6
2
3
The Extra Steps are:
1. Cross Multiply using Brackets (to remove fractions)
2. Identify the smaller letter term (letters both sides step)
3. Apply the Opposite Operation ( + or - ) to
this smaller item on both sides.
4. Simplify and Solve the Equation as normal.
Solve the Equation :
1a. Cross Multiply :
1b. Use Brackets :
1c. Expand Out :
n-3 = n+6
2
3
n-3 = n+6
2
3
3 (n - 3)
= 2 (n + 6)
3n - 9
= 2n + 12
Now solve as letter both sides (see next slide)
Finish off our previous question as a variable
both sides type question (Eg.Apply Opposites)
3n - 9
- 2n
n–9
+9
n
= 2n + 12
- 2n
= 12
+9
= 21
Solve the Equation : 8h + 7 = 3h - 4
2
1a. Cross Multiply : 8h + 7 = 3h -4
2
1b. Use Brackets :
1 (8h + 7)
1c. Expand Out :
8h + 7
1
= 2 (3h - 4)
= 6h - 8
Now solve as letter both sides (see next slide)
Finish off our previous question as a variable
both sides type question (Eg.Apply Opposites)
8h + 7
- 6h
2h + 7
-7
2h
/2
h
= 6h - 8
- 6h
= -8
-7
= -15
/2
= -7.5 or -7 ½
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