(1) (-8+√(64-4×1×（-4）))/2×1 =（-8+√80）/2 =（-8+4√5）/2 =-4+2√5 (2)(6+√(36-4×2×3))/2×3 =（6+√12）/6 =（6+2√3）/6 =(3+√3)/3
