\(1-\left(\dfrac{1}{5}+\dfrac{1}{7}\right)\)
\(=1-\left(\dfrac{7}{35}+\dfrac{5}{35}\right)\)
\(=1-\dfrac{12}{35}\)
\(=\dfrac{35}{35}-\dfrac{12}{35}\)
\(=\dfrac{23}{35}\)
\(=1-\left(\dfrac{7}{35}+\dfrac{5}{35}\right)\)
\(=1-\dfrac{12}{35}\)
\(=\dfrac{23}{35}\)
\(=\dfrac{1}{1}-\dfrac{1}{5}-\dfrac{1}{7}\)
\(=\dfrac{35}{35}-\dfrac{7}{35}-\dfrac{5}{35}\)
\(=\dfrac{23}{35}\)
=1- (7/35+5/35)
=1 - 12/35
= 23/35