Question 800656
Substitute the x and y values into both equations.  That point (2,6) must satisfy BOTH equations if the two equation lines intersect at this point.


{{{6=2*2+2}}}
{{{6=4+2}}}
{{{6=6}}}, already true.


{{{6=2.5*2+b}}}
{{{6=5+b}}}
{{{highlight(b=1)}}}.
That is the value you want.  


This second equation then must be {{{y=2.5x+1}}}