I searched your question and here is what I found:
Step-by-step explanation:
L = 4 + 3W (from the second condition)
L2 = 66 + LW (combining the first and third condition)
L2 = 66 + L(L-4)/3
3L2 = 198 + L2 -4L
2L2 + 4L -198 = 0
(2L - 18)(L + 11) = 0; discarding the negative root for lack of practicality , L = 9
from the first equation W = (L - 4)/3 = 5/3 = 1 2/3; 1.67
Hence the length of the rectangle is 9 cm and the width is 1.67 cm
check;
2nd condition; L = 4 + 3*1.67 = 9 (proven)
1st and 3rd condition; 92 = 66 + 9*1.67 = 81 (proven)