Answer:
length =29m width =11m
Step-by-step explanation:
length---L
width -----W
L=3W-4
area=319sqm
area of rectangle=L × W
area of rectangle =W ×(3W - 4)=319
expanding...
3W^2 - 4W=319
3W^2 - 4W -319=0
factorize
(W-11)(3W+29)=0
W=11 or -29/3
using the positive because the negative width with a minus sign does not make sense in real life, we use 11m
width =11m
length 3W -4=3(11) -4 =29m