Question

a plot of land doubles in size by adding x meters to the length and x meters to the width of the land. If the original plot had an area of 200 by 300 meters, what is the value of x

Answer 1

2*200*300=(200+x)(300+x)
120000=60000+200x+300x+x^2
x^2+500x-60000=0
(x+600)(x-100)=0
x=-600 or x=100
length is positive thus negative value is ignored. So answer is 100