<PRE><B>Question 686192</B>
solve this rational equation? 2/5+7/8=x/20
:
{{{2/5+7/8=x/20}}}
multiply by the least common multiple of the three denominators, that would be 40
40*{{{2/5}}} + 40*{{{7/8}}} = 40*{{{x/20}}}
Cancel the denominators and you have
8(2) + 5(7) = 2x
:
16 + 35 = 2x
:
51 = 2x
x = {{{51/2}}}
x = 25{{{1/2}}}</PRE>