I believe that the answer is 3+84x is this question wants you to simplify the expression.
Answer:
84x + 3
Step-by-step explanation:
3+3x+9(9x)
First 9 times 9x, which equals 81x
Then add the variables, so 3x + 81x and you get 84x
The equation is left as 84x + 3 because you can't add together a number with a variable and a number without a variable
