can my ga-78lmt-usb3 r2 motherboard be use for ryzen cpu. tyring to upgrade to ryzen 3 or 5 cpu.?

you showing off, it is a BS tool just to make the money on you

You're a very stupid person. You shouldn't be allowed to own nor even be near a computer, or any electronic for the matter

Sorry....... No!

Let me explain in a different way. Those old socket AM3+ motherboards like the one you have, has a 942 pin socket.  AMD Ryzen CPU's on the other hand have 1331 pins. So you won't be able to physically connect a Ryzen CPU to your motherboard. In addition to that, if you were to somehow find another way (which doesn't exist) to connect a Ryzen CPU to your AM3+ board, the lack of DDR4 support for Ryzen, and BIOS microcode recognition would keep your board from detecting a Ryzen CPU.

The best CPU you can use with your motherboard is the FX-8350 or FX-8370. Unfortunately these old "8-core" FX CPU's don't even hold a candle to a Ryzen 3 3100.

You'll need a socket AM4 board with preferably the b450 or b550 chipset to run the newest Ryzen 5000 series CPU's. x470 and x570 boards will also support Ryzen 5000 series processors. The first AMD AM4 boards that came out in 2017 had the 300-series chipset, such as b350 and x370, but some companies like Asus have not chosen to write an updated BIOS that would support the newest Ryzen processors for their x370 and b350 boards. 

No, to put it simply.

The Ryzen CPUs require a different motherboard socket and DDR4 RAM, which in turn requires a different motherboard chipset.

You will need a new motherboard and new RAM.

Check CPU support before you buy; some boards can only take earlier Ryzen CPUs when bought, others can take everything from Ryzen 3 to Ryzen 9.

please check maker's website under that board and the 'support' page for list of supported CPUs

No, sir, I'm afraid not.

The following webpage, from the Gigabyte website, shows you which CPUs are compatible with your motherboard.