a) The solution is the point where the lines intersect: (5, 2.5)
b) The horizontal line has equation
.. y = 2.5
The downward-sloping line can be written in intercept form as
.. x/10 +y/5 = 1
or in standard form as
.. x +2y = 10 . . . . . . . . . (multiply the above equation by 10)