Question 335232
<pre>
Here's how to check your answer when your answer is a fraction, and
there are fractions in the original problem:

{{{x/2}}}{{{""+""}}}{{{x/5}}}{{{""=""}}}{{{5/4}}}

Write the fractions involving the variable as divisions:

{{{"x÷2"}}}{{{""+""}}}{{{"x÷5"}}}{{{""=""}}}{{{5/4}}}

Then write them as multiplications by the reciprocals
("inverting the second then multiplying")

{{{"x"}}}{{{""*""}}}{{{1/2}}}{{{""}}}{{{""}}}{{{""+""}}}{{{""}}}{{{""}}}{{{
"x"}}}{{{""*""}}}{{{1/5}}}{{{""}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}
Now you can substitute your fraction answer:

{{{25/14}}}{{{""*""}}}{{{1/2}}}{{{""}}}{{{""}}}{{{""+""}}}{{{""}}}{{{""}}}{{{
25/14}}}{{{""*""}}}{{{1/5}}}{{{""}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

       {{{5}}}
{{{25/28}}}{{{""}}}{{{""}}}{{{""+""}}}{{{""}}}{{{""}}}{{{cross(25)/14}}}{{{""*""}}}{{{1/cross(5)}}}{{{""}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

{{{25/28}}}{{{""}}}{{{""}}}{{{""+""}}}{{{""}}}{{{""}}}{{{
5/14}}}{{{""}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

{{{25/28}}}{{{""}}}{{{""}}}{{{""+""}}}{{{""}}}{{{""}}}{{{
5/14}}}{{{""*""}}}{{{2/2}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

{{{25/28}}}{{{""}}}{{{""}}}{{{""+""}}}{{{""}}}{{{""}}}{{{
10/28}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

{{{35/28}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

Reduce the fraction on the left:

{{{5/4}}}{{{""}}}{{{""=""}}}{{{""}}}{{{5/4}}}

But the easiest way to check is to convert your answer to a decimal using a
calculator, then store it in the memory of your calculator, then type the left
side into your calculator recalling the value you stored for x, and see if
you get the same decimal answer on both sides.
 
Edwin</pre>