The legth of a rectangle is three times its width. if the width is diminished by 1 m and the legth increased by 3 m, the area will be 72 sq m. find the dimensions of the original rectangle?

Let width of rectangle be "x"

L = 3x W=x

if width is diminished by 1 that means new width = (x-1)

similarly the new length would be (3x+3)

hence (x-1) * (3x+3) = 72

(3x^2) - 3=72

3x^2=75

x^2=25

x = + / - 5

reject - 5 as you cant have negative length

hence x=5

so original dimensions of rectangle is

L = 15m W=5m