"If you subtract 12 from my number and multiply the difference by -15 ​, the result is -140​." What is ​'s ​number?

The answer would be 2.7. Am not very sure though

Step-by-step explanation:

So what you do is

for example the unkown number is x and the answer you get is y

12-x=y * -15=-140

-140/-15=9.33 (this is y the answer)

12-x=9.3

12-9.3=2.7

To check your answer

12-2.7=9.3

9.3 * -15=-139.5 if you round it then it would be -140

4 and 5)16.97 or 12√2

6)15.59 or 9√3

7)y = 15.59 or 9√3     x =27

8)17.80