Equation

My Definition

Key Characteristics

The following are true of an equation:

  • It is a mathematical statement saying two expressions are the same.

  • An equal sign joins the two expressions.

  • It may contain numbers, variables, grouping symbols, and/or operations.

  • In some cases, an equation that contains a variable (unknown) can be solved to determine the value of the unknown.


Example

These are examples of equations:
To model solving one- and two-step equations, one may use an interactive balance.
3 + 2 = 5
12 - 4 = 5 + 3
- 16 = 3
2x + 4 = 12
3(x + 4) = 15
2x - 2 = 3x + 4
x2 - 4 = 5

To use this interactive balance, one must have Java installed.

Non-example

These are examples of expressions, not equations:

5 + 2
12 ÷ 3 - 4(6 + 2)
(7 + 6)2

 - 8
5x + 6
2(x - 1)

These are examples of inequalities, not equations.


3 > x

2x – 2 < 3x + 4

TEKS: 1(5)(E), 1(5)(F), 3(5)(A), 3(5)(B), 3(5)(D), 4(4)(C), 4(4)(E), 4(5)(A), 5(4)(B), 6(6)(B), 6(6)(C), 6(7)(B), 6(8)(C), 6(9)(A), 6(9)(B), 6(9)(C), 6(10)(A), 6(10)(B), 7(7)(A), 7(10)(A), 7(10)(B), 7(10)(C), 7(11)(A), 7(11)(B), 7(11)(C), 8(5)(A), 8(5)(B), 8(5)(F), 8(5)(I), 8(8)(A), 8(8)(B), 8(8)(C), 8(9)(A)