VOCAB
A letter that represents a number is called a ___
variable
In 7x + 3, identify the variable.
x
A number is increased by 5
How many terms are in 3x - 5?
2
If x = 4, evaluate x + 6
10
Why do mathematicians use variables instead of numbers?
To represent unknown or changing values
In 7x + 3, what does the 7 represent?
Coefficient
Five less than a number
x - 5
Can 3x + 3 be simplified? If so, how?
No; unlike terms
Write an expression: "A number divided into three equal groups"
X/3 or X รท 3
In 5x, what does the five represent and what does it tell you to do?
Five is a coefficient; it tells us how many groups of x there are
In 4a + 7 + 2a, why are 4a and the 2a called "like-terms"?
Same variable and same exponent
Twice a number plus 3
2x + 3
Why can't 4x and 4y be combined?
Different variables
Simplify: 2x + 3x + 4 + x
6x + 4
Explain the difference between a coefficient and a constant.
A coefficient multiplies a variable while a constant stands alone
How many coefficients are in 6x + 3 + 2x, and what are they?
2 coefficients; 6 and 2
A number is multiplied by 4, then decreased by 6
4x - 6
Simplify and explain; 5x + 2 + 3x
8x + 2 (only combine like-terms)
True or False and explain: "x + 3 is the same as 3 + x"
True because of the commutative property of addition
If an expression has 3 terms, what must be true about it?
It has two + or - signs separating parts
5x and 2x are groups of x, the variable; 3 is a constant; the terms are the separated parts
A number is increased by 3, then it is multiplied by 2
2 (x + 3)
Explain why 3x + 5 + 2x becomes 5x + 5 instead of 10x.
Because only like-terms combine; constants say separate
A student says "In 4x + 3 + 2x, there are three variables". Do you agree or disagree?
Disagree; there is only 1 variable (x), repeated in multiple terms