1. x²+2x+8=x²+2*1*x+1²+7=(x+1)²+7
2. x²+6x+10=x²+2*3*x+3²+1=(x+3)²+1
3. x²-2x-5=x²-2*1*x+1²-6=(x-1)² -6
4. x²+8x-10=x²+2*4*x+4² -26=(x+4)² -26
5. -x²+4x-1=-(x²-4x+1)=-(x² -2*2*x+2² +1)=-((x-2)² +1)=1-(x-2)²
6. -x²+2x+1=-(x²-2x-1)=-(x²-2*1*x+1²-2)=-((x-1)² -2)=2-(x-1)²
7. x²+4x+7=x² +2*2*x+2² +3=(x+2)² +3
8. x²-2x-7=x² -2*1*x+1² -8=(x-1)² -8
9. x²-6x-8=x² -2*3*x+3² -17=(x-3)² -17
10. -x²-4x-3=-(x²+4x+3)=-(x²+2*2*x+2² -1)= -((x+2)² -1)=1-(x+2)²