Answer
$(9375+200x+x^2)$ yd $^2$
Work Step by Step
The new length of the field will be 125+x.
The new width of the fields will be 75+x.
The new area of the field will be
$(125+x)(75+x)\longrightarrow$ Use the FOIL method to multiply the binomials.
=$9375+125x+75x+x^2\longrightarrow$ Combine like terms.
=$9375+200x+x^2$
