4. Which graph represents the following system of equations?

y = 3x + 3
y = –x – 3

A. Graph c

B. Graph b

C. Graph d

D. Graph a

 Graph D (bottom right corner)

Explanation:

The equation y = 3x+3 is in slope intercept form y = mx+b

m = 3 = slope

b = 3 = y intercept

In this case, both the slope and y intercept are the same (though in general they tend not to be).

The positive slope value means the line goes uphill as you move from left to right. The positive y intercept means the diagonal line crosses the y axis somewhere above the horizontal x axis. Specifically, it crosses the y axis at y = 3

Graph D is the only graph that has such a line on it. Graphs A, B and C have the positive slope line where they have a negative y intercept, so we can rule them out.

You can use graphing tools such as Desmos or Geogebra to help confirm this answer. You could also make a table of values, and plot each point, to form the lines. Two points is the minimum amount needed to form any line.

answer: evaluate the objective function at each vertex to determine which - and -values, if any, maximize or minimize the function. example: find the minimum value and maximum value of the objective function f ( x , y ) = 4 x + 5 y , subject to the following constraints