Question 120198
PERIMETER=2L+2W 
AREA=L*W
60=2L+2W
200=L*W OR L=200/W NOW SUBSTITUTE (200/W) FOR L IN THE FIRST EQUATION & SOLVE FOR W
60=2(200/W)+2W
60=400/W+2W ADD THE 2 TERMS ON THE LEFT SIDE OF THE EQUATION BY FINDING A COMMON DENOMINATOR (W) THUS:
60=(400+2W*W)/W
60=(400+2W^2)/W NOW CROSS MULTIPLY
400+2W^2=60W
2W^2-60W+400=0
2(W^2-30W+200)=0
2(W-20)(W-10)=0
W-20=0
W=20 ANSWER FOR THE WIDTH & 10 FOR THE LENGTH. 
OR W-10=0
W=10 FOR THE WIDTH & 20 FOR THE LENGTH.
PROOF
60=2*10+2*20 
60=20+40
60=60
&
200=10*20
200=200