Answer:
Variables are the letters that represent a number. So, it would be the ones bolded here: 3x=12 and y=1/2x-6
The coefficients are next to the variables-the ones being multiplied with the variable. They are bolded here: 3x= 12 and y= 1/2x-6
The constants are the numbers that aren't coefficients or variables. So they are bolded here: 3x=12 and y=1/2x-6