Write a variable expression for 3 times the sum of a number and 5.

A) 5(x + 3)
B) 3x +5
C) 3(x + 5)
D) x + 15

B) 3x+5

Step-by-step explanation:

Let's suppose that x is equal to the sum of a number.  That means, that 3x needs to be somewhere in the variable equation.  "And 5", means to add, so +5 also needs to be somehwere in the equation.  Giving you 3x + 5 as the answer.  Now you might be thinking, "But what about C? Isn't it basically the same answer as B?"  The answer to THAT question is NO.  For it to be the same as B, you would have to get rid of the parenthesis.  This is because when there's a parenthesis, it means that it is the first thing you have to do in the equation.  But that is not what we want.  We do not want the sum of a number to be added to 5.  We want it to be multiplied by 3.  So that is why C is the not the same as B.  B is yoir correct answer.