An interesting problem having uneasy answers

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Consider $a,b,c\in\mathbb{R}-\{0\}.$ A real valued function $f$ is defined as $f(x,y,z)=2^y\cdot3^z\cdot a^x\cdot b^y\cdot c^z+2^z\cdot3^x\cdot a^y\cdot b^z\cdot c^x+2^x\cdot3^y\cdot a^z\cdot b^x\cdot c^y$, where $x,y,z\in\mathbb{Z}$. Given that $f(1,0,0)=4$ and $f(2,0,0)=6$ then

The possible value of $[a]$ $($where $[.]$ denotes the greatest integer function$)$ can be: Answer given is $0,1,2$

The integral values of $\frac{1}{b}$ can be: Answer given is $1,2,3$

If all possible values of $c$ satisfying given condition is $[p,q],$ then $4q-3p$ is equal to : Answer given is $2$

The maximum value of $[a]^2+[b]^2-[c]$ $($where $[.]$ denotes the greatest integer function$)$ is: Answer given is $5$

My work: We can form two equations: $$a+2b+3c=4$$ and $$a^2+4b^2+9c^2=6$$ After this, I wasn't able to do anything. Then I checked if there are solutions to this on Wolfram Alpha and I got two set of real solutions. $$a=\frac{2}{3},\:\:b=\frac{5}{6},\:\:c=\frac{5}{9}$$and $$a=2,\:\:b=\frac{1}{2},\:\:c=\frac{1}{3}$$ In both the cases, the value of $[a]$ is either $2$ or $0$. It can't be $1$. Likewise, there are many loopholes in the other given answers also. So this can mean two things. Either the printed answers are wrong, or WA is not giving full solutions $($ though I highly doubt this case$)$.

Also, how can one get two or more set of real solutions$?$ Do we have to form a parametric equation or do we have to apply some advance algebra$?$

I actually require the method by which we can get values of $a,b,c$ and then I can review the printed answers.

Any help is greatly appreciated.

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Try to form quadratica in all variables then apply the condition of real roots. You will get values of all variables having upper and lower bound.