Currently i using 2 samsung device,
A7 2016 and Tab A 2017
And i just carry charger that for A7 2016 charge both
As i see A7 fast charger is 9V 1.67A and 5V 2A
When i charge my tablet it take longer that charger come with tablet
Tablet charger show 5V 2A, about 3.5hrs full charge using A7 charger,
If using tablet charger just aboit 3hrs, both 5V 2A not same thing?

May be try one with QC 3.0 spec and see how?

Are you charging using the same USB charging cable (different charging adapter)? If not, try changing/swapping cable first.

Using original charger and cable
Both charger come with device

Any difference if you swap the cable? As in use tablet USB cable but with A7 charging adapter? I would do this first as it much cheaper to change cable than adapter.

Cannot use tablet cable to charge phone,
Tablet USB C, phone normal USB

Let me try to undersand this. You basically have the following 4 items:

A. Fast charging adapter (from A7)
B. Normal adapter (from tablet)
C. Micro USB cable (from A7)
D. Type C USB cable (from tablet)

You are using Fast Charging adapter (A) to charge both so:

A->C->Phone (no issue)
A->D->Tablet (slow)

But if you using Normal adapter (B) it is normal.

B->D->Tablet (no issue)

Is the above correct?

Yes, correct

I see. I think maybe the adaptive fast charging adapter is fallback into 5V/1.67A causing longer charging time.

That mean fast charger did not auto use 5V 2A?

Just my guess only. Also note that 2A is the max current, actual could be lower than that.

I think, sometimes it could also be limitation of the device itself only capable of charging at a set amount of amps.

Older Apple iPhones are a clear example of this as far as I know.