Final answer:
To find the value of an expression 3x + 4 when x=7, replace x with 7 in the equation to get 21 + 4. After doing the addition, we find that the value of the expression is 25.
Step-by-step explanation:
In math, to evaluate an expression means to find its value using the given information. Here, the expression is 3x + 4 and we're asked to evaluate this for x = 7.
Step 1: Substitute the value of x into the equation. Therefore, we replace x with 7.
3*7 + 4
Step 2: Follow the order of operations. First, do the multiplication, then the addition.
21 + 4 = 25
So, if x = 7, the value of the expression 3x + 4 is 25.
Learn more about Evaluating Expressions