Pls soon! : ) question- the difference of the square of a number and three times the sum of the number and 7 is more than the product of that number and 15. select the inequality that can be used to determine the unknown number. a. x2 + 3x ≥ 15 + x b. x2 - 3x + 7 ≥ 15x c. x2 - 3x - 21 > 15x d. x2 - 3x + 21 > 15 + x

C.

Step-by-step explanation:

Let x be the unknown number,

So, the square of the number =

Three times of the sum of number and 7 = 3(x+7),

Also, the product of the number and 15x,

Thus, The difference of the square of a number and three times the sum of the number and 7 is more than the product of that number and 15.

⇒  ( sign '>' is used for more than )

⇒   ( Apply distributive property on left side )

Hence, option 'C' is correct.