Answer
$y=-3$
Work Step by Step
Distribute 5 and 7 to have:
$5y-20=14y+7$
Subtract $7$ from both sides to have:
$5y-20-7=14y+7-7
\\5y-27=14y$
Subtract $5y$ from both sides to have:
$5y-27-5y=14y-5y
\\-27=9y
\\-3 = y$
Checking:
$\begin{array}{ccc}
\\5(-3-4) &\stackrel{?}{=}&7[2\cdot(-3)+1]
\\5(-7) &\stackrel{?}{=}&7[-6+1]
\\-35 &\stackrel{?}{=}&7(-5)
\\-35 &\stackrel{\checkmark}{=}&-35
\\\end{array}$
