1. Two step equation Operations

2. Introduction What is an equation?
An equation is a mathematical statement that
shows 2 quantities are equal. An equation contains
an equal sign.
12 – 3 = 9 Numerical
3a = 30 Algebraic

3. Steps for Solving One-Step Equations
1) Get the variable on one side of the equation.
2) You always perform the same operation to
both sides of an equation.
3) To undo an operation you perform its opposite
operation to both sides of the equation.

4. Opposite operations
The opposite of add is
SUBTRACT
The opposite of subtract is
ADD
The opposite of multiply is
DIVIDE
The opposite of divide is
MULTIPLY

5. Solving Equations Using Addition or Subtraction:
Rule 1: If a number has been added to the variable, subtract that number from both sides of the equation. Rule 2: If a number has been subtracted from the variable, add that number to both sides of the equation.

6. Solving Equations Using Multiplication or Division
Rule 3: If a variable has been multiplied by a non zero number, divide both sides by that number. Rule 4: If a variable has been divided by a number, multiply both sides by that number.

7. Example 1: Solve 4n + 7 = 15
Solution:
Equals = 4n 15
RHS
LHS
Variable/
Unknown 4n = 15
Constants
Get the variable on one side of the equation.
We keep variable n on the Left Handside(LHS) and move constant to the Right Handside(RHS) 4n =
15 - 7
By rule 1, 7 is added to the
variable, so subtract 7 from
both sides of the equation
By integer rule, if numbers
have different sign,
subtract the numbers and put sign of bigger number 4n = 8
By rule 3, a variable is
multiplied by 4,so divide b
oth sides by 4
Hint: 4n = 4 x n
n = 2
Ans: n = 2

8. = -12 + 7 = -12 + 7 - 7 = -12 - 7 = = Example 2: Solve Solution:
Equals =
-12
RHS
LHS
Variable/
Unknown
+ 7 =
-12
Constants
Get the variable on one side of the equation.
We keep variable j on the Left Handside(LHS) and move constant to the Right Handside(RHS) =
By rule 1, 7 is added to the
variable, so subtract 7 from
both sides of the equation
By integer rule, if numbers
have different sign,
subtract the numbers and put sign of bigger number =
-19 =
-19 x 2
By rule 4, a variable is divided
by 2,so multiply both sides by 2
Ans: j = -38
j = -38

9. Try these
7e – 4 = 31