We are tasked with finding all non-negative integer solutions (x,y,z) to the equation:
2x+9⋅7y=z3
Given that our solution must satisfy integer constraints and each variable is greater than or equal to zero, we will systematically explore potential solutions.
### Step 1: Analyze small values of z
Let's begin by examining small values for z since the cubic function grows rapidly and only a finite number of candidates will exist.
#### Sub-step: Calculate for z=0,1,2,3,4
z=0:2x+9⋅7y=03=0
This forces 2x=0 and 9⋅7y=0, which is impossible for x,y≥0.
z=1:2x+9⋅7y=13=1
This can only be satisfied by 2x=1 and 9⋅7y=0, which is impossible for integer y≥0.
z=2:2x+9⋅7y=23=8
Testing for x=0,1,2,3:
- x=3: 23=8, so 9⋅7y=0, y cannot be satisfied for y≥0.
z=3:2x+9⋅7y=33=27
Testing for small values of x and y:
- x=0: 20+9⋅70=1+9=10, not 27.
- x=1: 21+9⋅70=2+9=11, not 27.
- x=2: 22+9⋅70=4+9=13, not 27.
Trying with different values of y, we find that no combination of (x,y) results in 27−2x=9⋅7y.
z=4:2x+9⋅7y=43=64
For x=0, solve 1+9⋅7y=64:
- 9⋅7y=63 which yields 7y=7 and hence y=1.
The solution (x,y,z)=(0,1,4) satisfies 20+9⋅71=1+63=64=43.
### Conclusion
Therefore, the only solution with x,y,z≥0 satisfying the equation is:
(0,1,4)