Determine whether the following equations have a solution or not and justify your answer.

1. 5x² + 8x+7 =0
2. 7½y²-6y-13(7)½=0
3. 2x²+x-1 = 0
4. 4/3x²-2x+3/4 =0
5. 2x²+5x+5=0
6. p²-4p+4 =0
7. m²+m+1=0
8. 3z²+z-1 =0