Answer
$y=\dfrac{49}{9}$
Work Step by Step
Using the properties of equality, the solution to the given equation, $
\dfrac{9}{10}y-\dfrac{7}{10}=\dfrac{21}{5}
$, is
\begin{array}{l}
10\left(\dfrac{9}{10}y-\dfrac{7}{10}\right)=\dfrac{21}{5}(10)
\\\\
1(9y)-1(7)=21(2)
\\\\
9y-7=42
\\\\
9y=42+7
\\\\
9y=49
\\\\
y=\dfrac{49}{9}
.\end{array}
