Evaluating Variable Expressions

Front

What is a variable in mathematics?

Back

A symbol, often a letter, that represents a number in mathematical expressions or equations.

Front

What does it mean to evaluate a variable expression?

Back

To substitute the values of the variables into the expression and perform the necessary operations to find a numerical result.

Front

If x = 3, what is the value of the expression 2x + 5?

Back

2(3) + 5 = 6 + 5 = 11.

Front

What is the order of operations used when evaluating expressions?

Back

Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right) - often abbreviated as PEMDAS.

Front

Evaluate the expression 4a - 3b if a = 2 and b = 1.

Back

4(2) - 3(1) = 8 - 3 = 5.

Front

What is a constant in a mathematical expression?

Back

A fixed value that does not change, such as the number 5 in the expression 3x + 5.

Front

How do you simplify the expression 3(x + 4)?

Back

3x + 12.

Front

What is the difference between an expression and an equation?

Back

An expression is a combination of numbers, variables, and operations without an equality sign, while an equation states that two expressions are equal.

Front

If y = 4, what is the value of the expression y^2 - 2y + 1?

Back

4^2 - 2(4) + 1 = 16 - 8 + 1 = 9.

Front

What does it mean to substitute in an expression?

Back

To replace a variable with a specific value.