The letter x has two lines of symmetry.
90 divided by 2= 45 so x=45
2•45=90
So, for the next one y=60 because 90+90=180
3•60-2•45=90
They will make the same amount after 10 phones sold. Before that Plan A is the better plan. After 10, Plan B is the better plan.
You can find the point of intersection by modelling the two equations and setting them equal to each other. If x is equal to phones sold:
250 + 25x = 50x
250 = 25x
10 = x
Therefore, you make the same at 10 phones.
If you are asking if (2,14) would be a point on the line, it would not because:
14≠5*2+10
Hope this helps :)