Addition & Subtraction
x + 2 = 5
x = 3
5x = -10
x = -2
1/5a = 7
a = 35
The 5 steps to solving an equation are:
1.
2.
3.
4.
5.
Remember: "Don't Call Me After Midnight."
1. Distribute.
2. Combine Like Terms on each side.
3. Move the Variable to the left.
4. Add or Subtract the constant.
5. Multiply or Divide.
A variable represents an unknown value or unknown input.
a + 5 = 2
x = -3
-3x = 0
x = 0
9 = 2/3m
m = 27/2
An expression is made up of two or more _______>
A) equations
B) variables
C) constants
D) terms
The correct answer is D) terms.
Term: 3x, 3
Expression: 3x + 3
Equation: 3x + 3 = 6
Give an example of an equation with both a negative sign and a subtraction sign.
Example: -2x - 4 = 5
"negative two x minus four equals five"
x + 7 = -3
x = -10
-2/5x = 8
x = -20
-4/7x = 3
x = -21/4
The reciprocal of a number is __________.
Describe in your own words.
OR
An example of a reciprocal would be _______.
The reciprocal of a number is the multiplicative inverse of that number. In other words, it is the number that, when multiplied with the number, the product is equal to 1.
Example: the reciprocal of -2/3 is -3/2 because -2/3 times -3/2 equals 1.
What is the first step to solve this equation?
16 = -10x
Switch the sides, so that the variable 10x is on the right side and the constant 16 is on the left side.
-15 = x - 6
x = -9
5.6 = 1.4x
x = 4
-11.5x = 34.5
x = -3
How do we say this equation?
-2/3x - 5 = 10.6
____ two _____ three x _____ five _____ 10.6
-2/3x - 5 = 10.6
negative two over three x minus five equals 10.6
Simplify: 8/28
2/7
-27 = c + 27
x = -56
-4.8 = -0.4c
c = 12
-48.6 = -8.1k
"Isolate the variable" means to __________.
1) get the variable by itself.
2) solve for the variable.
3) determine the value of the variable that makes the equation true.
Describe and show 2 mistakes on the board that you or other students can make when solving one-step equations.
Answers vary. Teacher will verify.