Transcript ALGEBRA - Onondaga Central School District

ALGEBRA
LESSON 3 –
SOLVING ONE-STEP
ADDITION/SUBTRACTION
EQUATIONS
ONE-STEP EQUATIONS
• An equation is a statement that says
two expressions are equal
• To solve an equation containing a
variable means to find the value(s) of
the variable that make(s) the
equation true.
EXAMPLE: x = 4 is a solution to the
equation x + 6 = 10 because we all
know that 4 + 6 = 10
x = 11 is not a solution
because 11 + 6 is not equal to 10
SOLVING ONE-STEP
EQUATIONS
• A one-step equation is an
equation that requires only one
step to solve it
SOLVING EQUATIONS USING
INVERSE OPERATIONS
• In order to solve any equation, we
must use inverse operations
– the inverse of addition is
subtraction
– the inverse of subtraction is
addition
Essentially, you are trying to make it
so the “x” is isolated.
So, you are trying to make
everything that is not attached to
the “x” go away (turn into zero)
SOLVING EQUATIONS USING
INVERSE OPERATIONS
• If you see addition in an equation,
you will use subtraction to solve it.
• Same goes for subtraction, but you
use addition.
• REMEMBER: WHAT IS DONE TO ONE
SIDE OF AN EQUATION MUST ALSO
BE DONE TO THE OTHER SIDE
• ALWAYS CHECK YOUR ANSWER TO
MAKE SURE IT IS CORRECT
EXAMPLES OF
ADDITION/SUBTRACTION
EQUATIONS
• x + 8 = 10
The 8 is not attached to the x.
How can I turn 8 into a zero?
Show this! What you do to one
side, you must do to the other.
x + 8 = 10
CHECK:
-8
-8
2 + 8 = 10?
x = 2
10 = 10 yes
EXAMPLES OF
ADDITION/SUBTRACTION
EQUATIONS
• x – 9 = 11
Since the 9 is not attached to the
x, make it go away. What would
make 9 (in this case – 9) into
zero? Show this on both sides.
MORE EXAMPLES
ANY QUESTIONS??????
• HOMEWORK – Worksheet on
Addition/Subtraction Equations