Answer: x + 13.8 ≤ -4.2
Explanation:
"The sum of a number and 13.8" means that some number, we can use a variable, plus 13.8. I am going to use x as my variable, though it could be any other letter.
The next part, "is at most -4.2" means that x + 13.8 cannot be bigger that -4.2 when solved, but it can be -4.2. and so, this side of the inequality is:
≤ -4.2 (≤ mean less than or equal to)
Put both sides together and you get x + 13.8 ≤ -4.2.