Algebra Terms
A letter that stands for an unknown number, like x.
Variable
Solve for x: x + 7 = 15
x = 8
Solve for x: 2x + 3 = 11
x = 4
The distance around a shape.
Perimeter
The distance from the center of a circle to its edge.
Radius
In the expression 5x + 3, the 3 is this kind of term, a number that never changes.
Constant
Solve for y: y − 9 = 12
y = 21
Solve for y: 3y − 5 = 16
y = 7
The amount of flat space inside a shape, measured in square units.
Area
The number our class uses for pi.
3.14
In the expression 7y − 2, the 7 is this number multiplied by the variable.
Coefficient
Solve for n: 4n = 36
n = 9
Solve for n: 5n + 8 = 43
n = 7
The area of a rectangle with a length of 9 feet and a width of 4 feet.
36 square feet
The distance around a circle.
Circumference
A combination of numbers, variables, and operations with no equal sign, such as 4a + 6.
Expression
Solve for m: m ÷ 5 = 6
m = 30
Solve for x: x ÷ 4 + 6 = 10
x = 16
The perimeter of a square with sides that are each 8 centimeters long.
32 centimeters
Using 3.14 for pi, this is the circumference of a circle with a diameter of 50 inches.
157 inches
A math sentence with an equal sign, like 2x + 1 = 9.
Equation
lve for x: −4x = 32
x = −8
Solve for x: 3(x − 2) = 21
x = 9
A rectangle has a perimeter of 30 feet and a length of 10 feet. This is its width.
5 feet
Using 3.14 for pi, this is the area of a circle with a radius of 10 feet.
314 square feet