1400м,5400м,6900м,18000м,325000м,550000м
1) x = 3 + y => 4(3+y)+3y = 5
12+4y+3y = 5
7y = -7
y = -1 => x = 3-1 = 2
(2, -1)
2) x = 7+y => 5(7+y)-3y = 1
35+5y-3y = 1
2y = -34
y = -17 => x = 7-17 = -10
(-10, -17)
3) y = -2-2x => 6x+5(-2-2x) = 6
6x-10-10x = 6
-4x = 16
x = -4 => y = -2+8 = 6
(-4, 6)
1 ------- 3
x ------- 60
x = (60*1) : 3 = 20
ответ: можно поселить 20 рыбок