angle abc and ghk are equal by given. you set them equal and solve like this.
6x+2=5x-27+3x+1 combine like terms
6x+2=8x-26 subtract 6x from both sides
2=2x-26 add 26 to both sides
28=2x divide both sides by 2
x=14
measure of abc would be 6x+2 or 6(14)+2 or 86 degrees