1, 7Y+6=-6Y
13Y=-6
Y=-6/13
2. 2Y-3=7Y-7
5Y=4
Y=4/5
3. 0.5X-0.7=6.1-1.2X
1.7X=6.8
X=4
4. 1-3/2X+3X+5/2=0
1.5X=-3.5
X=-7/3