To find the value of 4x plus 9 when x is equal to 4, we start by substituting 4 in place of x in the expression.
The expression we have is:
4x + 9
Now, substituting x with 4:
4(4) + 9
Calculating this gives:
16 + 9
When we add 16 and 9, we get:
25
Therefore, the value of 4x plus 9 when x is 4 is 25.