Answer
$-8x+8y$
Work Step by Step
The given sentence translates to the expression, $
[(4x+5y)+(-5x+6y)]-(7x+3y)
.$ Removing the grouping symbols and then combining like terms, then the expression above simplifies to
\begin{array}{l}\require{cancel}
4x+5y-5x+6y-7x-3y
\\\\=
(4x-5x-7x)+(5y+6y-3y)
\\\\=
-8x+8y
.\end{array}