A:won’t be allowed; have finished
B:won’t allow; finish
C:won’t be allowed; will finish
D:won’t allow; will finish
分解因式:-12x4+8=____ ;(a2+1)2﹣4a2=____ .
x-6.2=4
x=____
解方程:x+1x-1+4x2-1=1.