both angles would equal the same so you have:
6x-57 = 2x+15
add 57 to each side:
6x = 2x+72
subtract 2x from each side:
4x = 72
divide:
x = 72/4 = 18
now replace x with 18:
6(18) - 57 = 51
2(18) +15 = 51
51 +51 = 102
Angle QNR = 102 degrees
