could someone help me solve this?

Question

The difference of two numbers is 6. Their sum is 30. Find the two numbers. \

all i can come up with is x-y=6 or x+y=30

 

could someone help me understand how to do this

Answer 1

Hi Jared

 

You are right. The problem needs to use both equations to find X and Y:

 

 X  - Y = 6     (Equation A)

 X + Y = 30   (Equation B)

 

If you multiply yhe Equation A by (-1) in both sides of the symbol "=", you have:

 

 -X  + Y = -6  (Equation A)

  X  + Y = 30  (Equation B)   If you add both equations, you get:

 

2Y = 24   Then, Y = 12

 

Substituting this value of Y in the Equation A:   -X + 12 = -6,  or   -X = -6 -12     Then, X = 18

 

Answer 2

Great start! You now have two equations (a system of equations).

You will notice that if you add your two equations together the y variable drops out  (= 0). You then have 2x=36.  x= 18. 

Substitute the 18 for x into either original equation and solve for y. 

y= 12