计算:(2a)="_____," 24xy-(-6xy)="_______," , =___
若 y=1-x+x-12的最大值是 a,最小值是 b,则 a2+b2的值为_____.
当 a=-12+5时,化简 9-6a+a2a-3+a2-2a+1a2-a的结果是_____.
若 a+b-2a-1-4b-2=3c-3-12c-5,则 a+b+c=_____.
a表示不大于 a的最大整数, {a}=a-a,设 ,a=13-7,b=13-7,则 a2+1+7ab=_____.
15+26+17+43=_____.