On this equation: 3(4v-1)-8v=17. you

First distribute the 3 into 4v-1  which will result in:
12v-3-8v=17

then add/subtract your v values, so 12v-8v, which leaves:
4v-3=17

then add 3 to both sides, which cancels it out on the left side, leaving:
4v=17+3  simplified to 4v=20

next divide both sides by 4, which cancels out the 4 on the left side, leaving:
v=20/4  simplified to v=5

Good luck!