Vocabulary
What is a variable?
A letter or symbol that represents an unknown value in an equation.
3x = ? x= 3
9
Solve x+4=9
x = 5
A train travels at x miles per hour for 3 hours and covers 150 miles. What is x?
x = 50
In the equation 3x+5=143x + 5 = 14, which part is the coefficient?
The number 3, because it is multiplied by xx.
16x = ? x= 2
32
Solve 2x−6=10
x = 8
The shorter side of a rectangle is 5 inches and the total perimeter is 30. What is the length of the longest side?
x = 10
The opposite of Division?
Multiplication
10x + 52 = ? x= 5
102
Solve 3x+5= 65
x = 20
A pizza costs $12, and each topping costs $1.50. If Maria paid $18 for her pizza, how many toppings did she add?
12+1.5x=18, so x=4x = 4. She added 4 toppings.
Something that doesn't change in an equation?
Constant
15 x -13 = ? x= 3
32
Solve 5 + 13 x = 57
x= 4
Emma bought 3 packs of pencils and a notebook for $18. The notebook costs $6. How much does each pack of pencils cost?
3x + 6 = 18, so x=4x = 4. Each pack of pencils costs $4.
What does it mean to "solve" an equation?
To find the value of the variable that makes the equation true.
22 x + 2 x + x - 16 = ? x = 2
56
1/4 x + 12 = 18
x = 24
A plumber charges a flat fee of $30 plus $20 per hour of work. If a customer paid $110, how many hours did the plumber work?
30 + 20x = 110, so x=4x = 4. The plumber worked for 4 hours.