Since the angles are supplementary, we know that they must add up to equal 180 degrees by the definition of supplementary angles
set the sum of the 2 angles to equal 180 and solve for x
6x + 48 + 60 = 180
6x + 108 = 180
6x = 72
x = 12
you could check to make sure that your x value is correct by plugging it back into the equation
6(12) + 48 + 60 = 180
72 + 48 + 60 = 180
120 + 60 = 180
180= 180
hope this helped!
