Question 46678
Simplify:
{{{3/10x + 9/14x^2}}}
To add these fractions, you need to find the common denominator.
A common denominator here is {{{70x^2}}}.  Why?  Because both {{{10x}}} and {{{14x^2}}} are factors of {{{70x^2}}}
{{{(10x)(7x) = 70x^2}}}
{{{(14x^2)(5) = 70x^2}}}, so...

{{{3(7x)/10x(7x) + 9(5)/14x^2(5)}}} Perform the indicated addition.
{{{(21x + 45)/70x^2}}} Factor a 3 from the numerator.
{{{3(7x + 15)/70x^2}}}