Question 1023424
{{{system((15x+60y)/90=45,x+y=45)}}}


{{{system((3x+12y)/90=9,y=45-x)}}}


{{{system(3x+12y=90*9,y=45-x)}}}


{{{system(x+4y=270,y=45-x)}}}


{{{x+4(45-x)=270}}} and then you continue......