Answer:
....x = the length of increase Initial area = 30*20=600m²
we increase the length by x m= 30+x
we increase the width by xm = 20+x
new area: (30+x)(20+x)=
600+30x+20x+x²=
x²+50x+600
and the new area is increased by 1400m²
x²+50x+600=1400+600
x²+50x+600-1400-600=0
x²+50x-1400=0
b²-4ac =50²-4(1*-1400)= 8100
delta=8100; V-delta = 90
(-b-Vdelta)= (-50-90)/2=-70
(-50+90)/2=20
a length is never negative, x=20
new length: 50
new width = 40
new area = 50*40=2000m²
% increase:
new length: 50 : [(50-30)/30]*100=66,6666= 66,7%
new width = 40 : [(40-20)/20]*100=100%
Explanation: