①a的平方+4ab-(-5-b的平方)
=a²+4ab+5+b²
=a²+2ab+b²+2ab+5
=-10+16+5
=11
②條件不足.已知a的平方+2ab=-10,b的平方+2ab=16,求①代數式a的平方+4ab-(-5-b的平方)的值;②代數式a²-c/2 + c-b²/2②(a²-c)/2 + (c-b²)/2=(a²-c+c-b²)/2=（a²-b²）/2=(a²+2ab-2ab-b²）/2=[(a²+2ab)-(2ab+b²)]/2=(-10-16)/2=-13 (少了括號，意義不一樣)