Both are equations in slope-intercept form:
y=mx +b
Where:
m= slope
b= y-intercept (where the line crosses the y axis)
One line crosses the y axis on y=3
And has a slope (rise /run = -3/2 = -1.5)
Y= -1.5x+3
Line 2:
b= -3
m= 1/3
y= 1/3x-3
System
y= -1.5x+3
y= 1/3x-3