Evaluating Algebraic Expressions
Evaluating Algebraic Expressions
Once variables are understood, the next step is assigning them values. Numbers can be substituted into expressions and simplified to produce a final answer.
Isaiah Lopez
Once variables are understood, the next step is assigning them values. Numbers can be substituted into expressions and simplified to produce a final answer.
Isaiah Lopez
Once you understand algebraic expressions, you can begin giving variables numerical values. Since variables represent unspecified values, they can be replaced with any number.
Suppose you have the expression x + 3, where x is a variable. If you are told to evaluate this expression for x = 2, you would simply replace all instances of x with a 2. Doing so in this situation would change the expression to 2 + 3, which equals 5. This means that for x = 2, the expression x + 3 results in the answer 5. As another example, suppose you need to evaluate the expression 4x − 7 for x = 2. Replacing x with 2 would result in the expression 4(2) − 7, which would simplify to 8 − 7 and then 1, which is the final answer.
If you have an expression with multiple variables, the same rule applies. You simply replace the variable with the value it is assigned. Suppose you have the expression 2x + y − 3, and you need to evaluate it for x = 3 and y = 1. In this instance, you would simply replace the value of x with 3 and the value of y with 1, resulting in the expression 2(3) + 1 − 3. This would then simplify to 6 + 1 − 3 and then 4, which is the final answer.