The zeroth derivative of a function
is simply the function itself, so the zeroth order linear ODE takes the general form

whose solution is
.
The cost of Tulip and Roses are 1500LL and 2500LL respectively
X=-3 and y=5
2x+y=-1
-x+3y=18
3y-18=x
2(3y-18)+y=-1
6y-36+y=-1
7y=-1+36
7y=35
y=35/7
y=5
-x+3y=18
-x+3(5)=18
-x+15=18
-x=18-15
-x=3
x=-3
-2(3z+8)=1/3(9-18z)
-6z-16=1/3(9-18z)
-6z-16=1/3(-18z+9)
-6z-16=1(-18z+9)
———-
3
0=57
The input has no solution