Choose the expression that mathematically represents the difference between ‘3 times a number’ and the quantity ‘5 times another number less 7’ a. 3x − (7 − 5x) b. 3x − (5y − 7) c. 3x − (5x − 7) d. 3x − (7 − 5y)

b. 3x - (5y -7)

Step-by-step explanation:

Let x represent "a number". Let y represent "another number."

The "3 times a number" is represented by 3x.

And "5 times another number less 7" is represented by 5y -7.

The difference between these quantities is the second subtracted from the first:

... 3x - (5y -7) . . . . matches selection b.

  or  

sin y = 7/q

7 is the opposite side length, q is the hypotenuse

tan y = 7/r

7 is the opposite side length, r is the adjacent side length

using sohcahtoa ^^^^

cos y = adjacent/hypotenuse

cos y = r/q