Multiply the first equation with (-1)
you should get this
-6r + 3t = -6
6r + 8t = -16
start to eliminate
11t = -22
divide by 11
t = -2
substitute
6r - 3(-2) = 6
6r + 6 = 6
6r = 6 - 6
6r = 0
r=0
Cost per meter(C) = $60/m
Length of rectangular field(L) = 50m
L = 2W
-> W = L/2
-> W = 50/2
-> Width of rectangular field = 25m
Cost of one field length(l) = L x C
-> l = 50 x 60
-> l = $3000
Two of the lengths of the field = 2 x l
-> 2 x $3000
-> $6000
Cost of one field width(w) = W x C
-> w = 25 x 60
-> w = $1500
Two of the widths of the field = 2 x w
-> 2 x $1500
-> $3000
Cost of fencing entire field = $6000+$3000
Hence, total field cost = $9000
Idk...................................
