Question

A number is equal to 3 times a smaller number. Also, the sum of the smaller number and 4 is the larger number. The situation is graphed on the coordinate plane below, where x represents the smaller number and y represents the larger number.
Which two equations represent the situation?

Answer 1

1. You have that:

 -  "x" represents the smaller number and "y" represents the larger number. 
 - A number is equal to 3 times a smaller number: y=3x
 -  The sum of the smaller number and 4 is the larger number: y=x+4

 2. Therefore, you have the following system of equations:

 y=3x   (i)
 y=x+4   (ii)

 3. When you solve it, you obtain:

 3x=x+4
 3x-x=4
 2x=4
 x=2

 y=3x
 y=(3)(2)
 y=6

 4. Which two equations represent the situation? The answer is:

 y=3x 

 y=x+4