[tex] \frac{7}{2} x - \frac{1}{2} y = \frac{9}{2} same \: as \: 7x - y = 9[/tex]
7x-y=9
3x-y=5 (multiply by -1 both sides of the equation)
7x-y=9
-3x+y=-5 (now add both equations)
7x-3x-y+y=4
4x=4 (divide by 4 both sides of the equation)
x=1
y=3x-5=3×1-5=-2
y= -2
answer: x=1, y=-2