Expressions
Identify the coefficient in:
6x + 4
6
A rectangle has:
Length = x + 3
Width = 4
write an expression representing area.
4(x + 3)
a balanced hanger represents:
x + 4 = 10
what is x?
x = 6
solve:
x + 7 = 15
x = 8
a wildlife researcher sees the expression:
5x
If x represents the number of deer in deer in one group, what does 5x represent?
the number of deer in 5 groups
Use distributive property to rewrite:
3(x + 5)
3x + 15
Find the perimeter of a rectangle with:
Length = x + 2
Width = 3
2(x + 2) + 2(3)
2x + 4 + 6
2x + 10
A hanger represents:
2x = 14
what is the value of each x?
x = 7
solve:
4x = 28
x = 7
A wildlife preserve has x deer.
After 12 more deer arrive, there are 30 deer.
Write an equation to represent this.
x + 12 = 30
Which expression is equivalent to:
4(2x + 3)
A. 8x + 3
B. 6x + 7
C. 8x + 12
D. 4x + 12
C. 8x + 12
A rectangle space has:
Length = x + 5
Width = 4
if x = 3, what is the area?
Length:
3 + 5 = 8
Area:
8 x 4 = 32
Area = 32
a hanger represents:
2x + 4 = 16
what should you do first to both sides?
subtract 4 from both sides to get 2x = 12
3x + 5 = 26
3x = 21
x = 7
Solve this equation:
3x + 6 = 30
3x = 24
x = 8
Create an equivalent expression for:
6x + 18
6(x + 3)
A rectangle has
length = 2x + 3
width = x
write and simplify an expression for the perimeter
2(2x + 3) + 2x
4x + 6 + 2x
6x + 6
a student has:
3x + 6 = 24
the student simplifies the equation to:
3x = 24
What did they do incorrectly?
They only subtracted 6 from one side when they should have subtracted 6 from both sides
solve:
2(x + 4) = 20
method 1:
2x + 8 = 20
2x = 12
x = 6
A wildlife researcher tracks 4 equal groups of deer plus 8 additional deer.
There are 36 deer total.
Write and solve an equation to determine how many deer are in each group.
4x + 8 = 36
4x = 28
x = 7
A students says:
5(2x + 4) = 10x + 9
Is the student correct? Why?
No.
the 5 must be distributed (multiplied) by both terms.
the correct answer is:
10x + 20
A rectangular classroom has:
Length = 3x + 2
Width = x + 4
Write a simplified expression for its perimeter.
Then evaluate the perimeter when x = 5.
2(3x + 2) + 2(x + 4)
6x + 4 + 2x + 8
8x + 12
Substitute x = 5:
8(5) + 12
40 + 12
52 units
a balanced hanger represents:
4x + 8 = 2x + 20
explain how we can solve for x.
subtract 8 from both sides and 2x from both sides:
2x = 12
divide both sides by 2:
x = 6
solve:
3(x + 5) - 4 = 26
3x + 15 - 4 = 26
3x + 11 = 26
3x = 15
x = 5
A researcher says:
"Five equal groups of animals plus 10 additional animals gives a total population of 45."
1. Define x.
2. Write an equation.
3. Solve the equation.
4. Explain what your answer means.
x = number of animals in each equal group.
5x + 10 = 45
5x = 35
x = 7
What does it mean?