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Solve the Equation :

3n + 5 = 2n + 7

We cannot solve this Equation using “Onion
Skins” or “Back-Tracking”, because our
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 :

3n + 5 = 2n + 7

The Extra Steps are:
1. Identify the smaller letter term.
2. Apply the Opposite Operation ( + or - ) to
this smaller item on both sides.
3. Simplify and Solve the Equation as normal.
3n + 5 = 2n + 7
Step 1. Identify the smaller letter term.

3n + 5 = 2n + 7
Step 2. SUBTRACT it from both sides

3n + 5 = 2n + 7
-2n
-2n
n+5=
7
Step 3. Solve as normal (See next slide)
Step 3. Solve the Equation :

n+5=7

n+5=7
To solve the Equation work from the biggest outer
skin, inwards through the smaller skins, applying
opposites, until we reach the letter variable.

Solution for n is 7 - 5 = 2
11 – 5h = 3h + 3
-

Step 1. Identify the smaller letter term.

11 – 5h = 3h + 3
-

Step 2. ADD it to both sides

11 – 5h = 3h + 3
+5h +5h
11
= 2h + 3
-

Step 3. Solve as normal (See next slide)
11 = 2h + 3 is the same as 2h + 3 = 11

2h + 3 = 11
To solve the Equation work from the biggest outer
skin, inwards through the smaller skins, applying
opposites, until we reach the letter variable.

Solution for h is 11 - 3

2 =4
Solve :

5(n + 1) = 2(n + 20)

We cannot solve this Equation using “Onion
Skins” or “Back-Tracking”, because our
Brackets and the Variable letter “n”
are on both sides of the Equation.
WE NEED TO EXPAND THE BRACKETS
BEFORE WE CAN SOLVE THE EQUATION
5(n + 1) = 2(n + 10)
5(n + 1) = 2(n + 10)
5n + 5 = 2n + 20
Now Solve a Letters Both Sides Equation

5n + 5 = 2n + 20
-2n
-2n
3n + 5 =
20
Step 3. Solve as normal (See next slide)
We can solve 3n + 5 = 20 with Onion Skins

3n + 5 = 20
To solve the Equation work from the biggest outer
skin, inwards through the smaller skins, applying
opposites, until we reach the letter variable.

Solution for h is 20 - 5

3 =5
Working Out Steps are:
1. Expand any Brackets First
2. Identify the smaller letter term.
3. Apply the Opposite Operation ( + or - ) to
this smaller item on both sides.
4. Simplify and Solve the Equation as normal*.
(* Use Onion Skins, Algebra Reversing,
or Backtracking with Flowcharts )
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All Images and Diagrams are Copyright by Passy’s World of Mathematics

Equations with Variables on Both Sides

  • 1.
  • 2.
    Solve the Equation: 3n + 5 = 2n + 7 We cannot solve this Equation using “Onion Skins” or “Back-Tracking”, because our Variable letter “n” is on both sides of the Equation.  WE NEED TO DO SOME EXTRA STEPS BEFORE WE CAN SOLVE THE EQUATION
  • 3.
    Solve the Equation: 3n + 5 = 2n + 7 The Extra Steps are: 1. Identify the smaller letter term. 2. Apply the Opposite Operation ( + or - ) to this smaller item on both sides. 3. Simplify and Solve the Equation as normal.
  • 4.
    3n + 5= 2n + 7 Step 1. Identify the smaller letter term. 3n + 5 = 2n + 7 Step 2. SUBTRACT it from both sides 3n + 5 = 2n + 7 -2n -2n n+5= 7 Step 3. Solve as normal (See next slide)
  • 5.
    Step 3. Solvethe Equation : n+5=7 n+5=7 To solve the Equation work from the biggest outer skin, inwards through the smaller skins, applying opposites, until we reach the letter variable. Solution for n is 7 - 5 = 2
  • 6.
    11 – 5h= 3h + 3 - Step 1. Identify the smaller letter term. 11 – 5h = 3h + 3 - Step 2. ADD it to both sides 11 – 5h = 3h + 3 +5h +5h 11 = 2h + 3 - Step 3. Solve as normal (See next slide)
  • 7.
    11 = 2h+ 3 is the same as 2h + 3 = 11 2h + 3 = 11 To solve the Equation work from the biggest outer skin, inwards through the smaller skins, applying opposites, until we reach the letter variable. Solution for h is 11 - 3 2 =4
  • 8.
    Solve : 5(n +1) = 2(n + 20) We cannot solve this Equation using “Onion Skins” or “Back-Tracking”, because our Brackets and the Variable letter “n” are on both sides of the Equation. WE NEED TO EXPAND THE BRACKETS BEFORE WE CAN SOLVE THE EQUATION
  • 9.
    5(n + 1)= 2(n + 10) 5(n + 1) = 2(n + 10) 5n + 5 = 2n + 20 Now Solve a Letters Both Sides Equation 5n + 5 = 2n + 20 -2n -2n 3n + 5 = 20 Step 3. Solve as normal (See next slide)
  • 10.
    We can solve3n + 5 = 20 with Onion Skins 3n + 5 = 20 To solve the Equation work from the biggest outer skin, inwards through the smaller skins, applying opposites, until we reach the letter variable. Solution for h is 20 - 5 3 =5
  • 11.
    Working Out Stepsare: 1. Expand any Brackets First 2. Identify the smaller letter term. 3. Apply the Opposite Operation ( + or - ) to this smaller item on both sides. 4. Simplify and Solve the Equation as normal*. (* Use Onion Skins, Algebra Reversing, or Backtracking with Flowcharts )
  • 12.
    http://passyworldofmathematics.com/ All Images andDiagrams are Copyright by Passy’s World of Mathematics