Question 910661
Get slope from the two given intercepts and find y-intercept as equal to the constant term in the slope-intercept form.  You can then convert to standard form and read a and b directly.


Your slope is {{{m=(-3)/(-7/3)=3/(7/3)=9/7}}}, which might be useful enough on its own without going further - but not sure, so....


{{{y=(9/7)x-3}}}, should now be clear enough as the equation for the line having the unknown a and b.


Division of both sides by 3 might be a good idea so as to have the constant term as 1, or later(?) negative 1.

{{{y/3=(9/7)x/3-3/3}}}
{{{y/3=(3/7)x-1}}}
{{{-(3/7)x+y/3=-1}}}, Although standard form was mentioned, I am not in fact using it.
{{{(3/7)x-y/3=1}}}
{{{highlight(x/(7/3)+y/(-3)=1)}}}, which is the form given for your unknown line equation.


{{{highlight(a=7/3)}}}   and   {{{highlight(b=-3)}}}