Final answer:
The solution to the inequality 21x−12x<354 is x < 39.33, which corresponds to option D. x > 39.
Step-by-step explanation:
To solve the inequality 21x - 12x < 354, we need to simplify the expression first:
21x - 12x < 354
(21 - 12) x < 354
9x < 354
To isolate x, divide both sides of the inequality by 9:
x < 354/9
x < 39.33
However, since this is an inequality, we use the '<' symbol, not the '<=' symbol. Therefore, the solution is x < 39.33, which corresponds to option D. x > 39.