Given a & # 178; + B & # 178; = 12, ab = - 3, then (a + b) &# 178; =?, (a-b) &# 178; =?

Given a & # 178; + B & # 178; = 12, ab = - 3, then (a + b) &# 178; =?, (a-b) &# 178; =?


(a+b)²=a^2+b^2+2ab=12-3*2=6
(a-b)²=a^2+b^2-2ab=12-2*(-3)=18



a-1/a+2÷a²-2a+1/a²-4×a+3/a²+a-6


a-1/a+2÷a²-2a+1/a²-4×a+3/a²+a-6
=a-1/a+2÷(a-1)²/(a+2)(a-2)×(a+3)/(a-2)(a+3)
=(a-1)/(a+2)×(a+2)(a-2)/(a-1)² ×1/(a-2)
=(a-2)/(a-1) ×1/(a-2)
=1/(a-1)



(2a-1)²-2×(2a-1)×(a-6)+(a-6)²


(2a-1)²-2×(2a-1)×(a-6)+(a-6)²
=(2a-1-a-6)²
=(a-7)²