I need to loosen very tight bicycle brakes(pads). This is the only thing running over the cable, have no idea what it is and don't have many tools to begin with so assuming I don't have what is needed to loosen this:
There is more than one way to adjust brake pad "tightness" (I'm assuming this means that the brake pads are too close to the rim).
To answer the question. Pictured is the brake cable anchor bolt. The one pictured looks like a 10mm. There are three possible sizes, 10mm, 9mm or 8mm. You can find the correct size wrench or use an adjustable wrench (carefully). Losening the nut will allow the cable to slip through a hole in the bolt increasing the distance between the brake pads and the rim.
There are adjusting barrels on the levers. It may be possible to screw the adjusting barrel into the lever effectively making the cable longer without any tools.