Let x and y represent angles 1 and 2, respectively. The given relations tell you
... x + y = 180 . . . . the sum of measures of a linear pair is 180°
... y = 2x + 6 . . . . angle 2 is 6 more than twice angle 1
One way to solve these is to add twice the first equation to the second.
... 2(x + y) + (y) = 2(180) + (2x +6)
Now, subtract 2x
... 3y = 366
... y = 122 . . . . divide by the coefficient of y
The measure of angle 2 is 122°.