Question 899375
{{{3.5*10^(-6)(15-s)^2=2.5*(10^-6)*s^2}}}
Divide both sides by {{{10^(-6)}}}
{{{3.5*(15-s)^2=2.5*s^2}}}
{{{(7/2)(15-s^2)=(5/2)s^2}}}
Multiply both side by {{{2}}}
{{{7(15-s)^2=5s^2}}}}
{{{7(225-30s+s^2)=5s^2}}}
{{{1575-210s+7s^2=5s^2}}}
{{{highlight(2s^2-210s+1575=0)}}}
That's not the same answer as the one you stated. 
Your given answer would be (multiplying the equation by {{{20/3}}} to match the leading coefficient),
{{{2s^2-200s+1500=0}}}