Turn 3/4 into a fraction with a denominator of 8 by multiplying both the numerator and denominator. so you'll get 6/8 for the first one. 3/4+1/8=7/8
The image I included should help you solve the problem
In the first problem M bisects like AB. Because one side is thirteen we know the other side is too. So in total the line is 26. The ray MC bisects the line AB in line two. One side is eight so the other is eight. The line in total is 16