Question

Find the dimensions of a rectangle whose width is 10 miles less than its length and whose area is 75 square miles.

L= ?
W= ?

Answer 1

length = L
width =( L-10)

Area of rectangle =L*(L-10)

L*(L-10) = 75
L²-10L-75 = 0 -75= (-15)*5, -10= - 15+ 5
(L-15)(L+5)=0
L=15,L=-5

We can take only positive root,
so L=15 mi.
W=L-10=15-10=5
W=5 mi

Answer: L=15 mi, W=5mi.