Algebra 2 (1st Edition)

The whole garden is $16\cdot25=400$ square feet. If we have $x$ tomato plants and $y$ pepper plants, then our equation for the occupied area is: $8x+5y=400$. Thus if $x=15$, then $8\cdot15+5y=400\\120+5y=400\\5y=280\\y=56$