Since 5z⋅7w+1 is even, we have x≥1.
Case 1: y=0. The equation to be solved becomes
2x−5z⋅7w=1.
If z=0, then 2x≡1(mod5). It follows that 4∣x. Thus 3∣2x−1, which contradicts to 2x−5z⋅7w=1.
If z=0, then
2x−7w=1.
When x=1,2,3, a direct computation shows that (x,w)=(1,0),(3,1) are the solutions.
When x≥4, 7w≡−1(mod16). By direct computation we know that this is impossible.
Consequently, when y=0 all non-negative integer solutions of the equation are
(x,y,z,w)=(1,0,0,0),(3,0,0,1).
Case 2: y>0 and x=1. Thus the equation to be solved becomes
2⋅3y−5z⋅7w=1.
Hence −5z⋅7w≡1(mod3), i.e., (−1)z≡−1(mod3). It follows that z is odd.
Thus
2⋅3y≡1(mod5).
y≡1(mod4).
When w=0, we have 2⋅3y≡1(mod7). Thus y≡4(mod6), which contradicts to the fact y≡1(mod4). Hence w=0 and
2⋅3y−5z=1.
When y=1, we have z=1. If y≥2, then 5z≡−1(mod9), which implies z≡3(mod6). Thus 53+1(mod5z+1), so 7(mod5z+1), which contradicts to 5z+1=2⋅3y. Hence in this case we have only one solution
(x,y,z,w)=(1,1,1,0).
Case 3: y>0 and x≥2. Thus
5z⋅7w≡−1(mod4), and 5z⋅7w≡−1(mod3).
That is,
(−1)w≡−1(mod4), and (−1)z≡−1(mod3).
Thus z and w are odd. It follows that
2x⋅3y=5z⋅7w+1≡35+1≡4(mod8).
Hence, x=2, and
4⋅3y−5z⋅7w=1 (where z and w are odd).
Thus,
4⋅3y≡1(mod5), and 4⋅3y≡1(mod7).
From the above two congruencies we have y≡2(mod12).
Set y=12m+2, m≥0, then
5z⋅7w=4⋅3y−1=(2⋅36m+1−1)(2⋅36m+1+1).
Since
2⋅36m+1+1≡6⋅23m+1≡6+1≡0(mod7),
and
(2⋅36m+1−1,2⋅36m+1+1)=1, so 5∣2⋅36m+1−1.
Thus
2⋅36m+1−1=5z,
2⋅36m+1+1=7w.
If m≥1, by Equation (2) we have 5z≡−1(mod9), and from Case 2 we know that this is impossible.
If m=0, then y=2, z=1 and w=1. Thus in this case, we have only one solution
(x,y,z,w)=(2,2,1,1).
Consequently, all non-negative integer solutions are
(x,y,z,w)=(1,0,0,0),(3,0,0,1),(1,1,1,0),(2,2,1,1).