Answer:
First find the slope of the straight line, m=(Y2-Y1)/(X2-X1)=(17–7)/(-5–0)=-2.
Using the standard equation of a straight line, y=mx+b, we know that m=-2.
Thus, so far we know that y=-2x+b.
Now plug in the coordinates of either of the above points, that we know do lie on the straight line, into our equation, y=-2x+b, and solve for b.
I will use the first point, (0,7), to get 7=(-2)(0)+b.
Solving for b, we see that b=7.
Therefore, the equation of the straight line is y=-2x+7.
It is a good idea to check your answer on a graphing calculator.