Answer
$x^{2}+200x+9375$
Work Step by Step
New length= x+125 yd.
New width= x+75 yd.
New area:
$= (x+125)(x+75)$
$...$distribute the second factor, $x+75$.
$=x(x+75)+125(x+75)$
...distribute $x$
$=x^{2}+75x+125(x+75)$
...distribute $125$.
$=x^{2}+75x+125x+9375$
...gather like terms.
=$x^{2}+200x+9375$
