Step-by-step explanation:
let the width = y
the length =y-10
area of rectangle=length ×breadth
171 =y-10×y
171=y^2-10y
it turns into quadratic equation
y^2-10y+171=0
cant be solved by factorization therefore use general formula
y=-b+or-√(b^2-4ab)/2a
a=1 (coefficient of y^2) ,b=-10 , c=171
y=--10+or-√{10^2-4(1)(10)}\2(1)
y=10+or-√{100-40}\2
y=10+or-√60/2
y=10+or-(7.74/2)
y=10+3.87
y=13.87cm
OR
y=10-3.87
y=6.13cm
if y=13.87 then width is 13.87&length is 13.87-10
=3.87
OR
if y=6.13 then width is 6.13&length is 6.13-10=-3.87
