The sum of 237 and six times the opposite of a number is 405. what is the number?

a. - 28

b. - 24

c. 30

d. 32

The number is 28.

The equation would be:

237 + 6 (x) = 405

The problem states that 6 times the opposite of a number, however, since the number sign was not given, we do not know whether it is in a positive or negative form. So we leave it as only x.

237 + 6x = 405

6x = 405 - 237

6x = 168

6x / 6 = 168 / 6

x = 28

To check:

237 + 6 (28) = 405

237 + 168 = 405

405 = 405