Question

X - y = 3 x + 3y = 9

Answer 1

Solve for one of the variables in the first equation (in this case, I will solve for X):
X = Y + 3

Then use that value of X in the second equation to solve for Y:
X + 3Y = 9
(Y + 3) + 3Y = 9
4Y + 3 = 9
4Y = 6
Y = 1.5

Use the value of Y we just found in the X equation we created:
X = Y + 3
X = 1.5 + 3
X = 4.5

Therefore X = 4.5 or 9/2 and Y = 1.5 or 3/2.

Answer 2

X - y = 3 is the same as x=3+y  

3+y+3y = 9  

3+4y=9  

4y=9-3 

 4y=6 

 y=6/4 

 y=3/2  

x-(3/2)=3  

x=3+(3/2)  

x=6/2+3/2  


x=9/2