AnimeLover

b = 14, because if you backtrack it will become14. So b is being dividing by -7 ; -b/7 ; and the answer is -2. The opposite of dividing is multiplying, so you just need to multyply -7 and -2 that is 2 

 Work:

-b/7 = -2 

-7*-2

14

b = 14

"A decimal number is a number with a decimal point in it, like these: 1.5 .6 3.14. The number to the left of the decimal is an ordinary whole number. The first number to the right of the decimal is the number of tenths (1/10's)." - Google

um... did you meant 5*3/6?

(2x−5) (5x−1)

9/16 because you need to multiply the number; 3/4; two times

Merry Christmas to you too! 

thanks

pie = 1.77245385

There is no largely accurate fraction representation of pi without having to use an infinitely large number of digits in both the numerator and denominator.  An approximation often used is 22/7, but a more accurate one would be 355/113.
13/4 
16/5 
19/6 
22/7 - Most commonly used in school.
179/57 
201/64
223/71