On solving equations in the box 1:
-5x+y=10 -> 1
-25x+5y=50 ->2
div by -5 on equation 2.
so we get as 5x-y=-10 ->3
so solving 1 and 3 we get the equations cancel each other.so x and y are not true.They dont have any solutions.
On solving the equations in the box 2:
3x -7y =9 -->1
-4x +5y =1 -->2
so lets multiply equation 1 by 4 and euqation 2 by 3 so we get
12x-28y=36
-12x+15y=3
on solving we get -13y=39
y=-3 ,we can get x value by putting y value in any of the above equations.
3x-7(-3)=9
3x+21=9
3x=-12
x=-12/3
x=-4 so we get x=-4 and y=-3
On solving the equations in the box 3:
y=6x-2
by re-arranging we get -6x+y=-2 ---> 1
y=6x-4
on re arranging we get -6x+y=-4 ----->2
multiplying equation 2 by -1
so we get 6x-y=4 ---> 3
on solving 1 and 3 we get them cancel eachother so they have no solutions.
so finally analyzing all the boxes we can conclude that box 2 more number of solutions