Question 879616
The main denominator has two other denominators of 7 and 9.  Multiply the entire complex fraction by {{{1=(7*9)/(7*9)}}}, and simplify from that.


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Multiplication by 1 does not change the meaning of the number.  Multiplying a fraction by a lowest common denominator will clear the denominators.

That means, form this:

{{{(10/((5/7)+(2/9)))((7*9)/(7*9))}}}, and simplify the result from there.