Question 59761
{{{ 4s / (s^2 + 3s) }}}
to find the excluded values ... work only the denominator
{{{ s^2 + 3s }}}
factor out an s
{{{ s(s+3) }}}
set both equal to zero
{{{ s = 0 }}} and {{{ s + 3 = 0 }}}
{{{ s = 0 }}} and {{{ s = -3 }}}
either of these two values will make the demoninator zero and we do not want that.