a^2+2a-15=0a²+2a+1=16(a+1)²=161/a+1 - a+2/a^2-1 / (a+1)(a+2)/a^-2a+1=1/(a+1) -(a+2)/(a+1)(a-1) ×(a-1)²/(a+1)(a+2)=1/(a+1)-(a-1)/(a+1)²=(a+1-a+1)/(a+1)²=2/(a+1)²=2/16=1/8