I have two functions
f1= 45.7*x – 600 and
f2= -0.426*x +240
If I plot them in the same plot I got Plot1
I want to kind of combine them together so I got something like Plot2
However I am not quite sure how the equation of the function on plot 2 will look like based on the coefficients of my two functions. Can someone help me out with it?
Best Answer
$$f1=f2\iff 45.7\cdot x-600=-0.426\cdot x+240 \iff 45.7\cdot x+0.426\cdot x=240+600$$ $$\iff x=\frac{840}{46.126}\approx18.211.$$ So your functions intersect at the point with x-coordinate $18.211$. The function your plot2 shows is thus $$f(x) = \begin{cases}f_1(x)\ \mbox{ if }\ x\leq18.211\\ f_2(x)\ \mbox{ if }\ x>18.211 \end{cases}$$ How to plot this function depends on the software you are using.