A: Touch this sofa. Is it____? B: No. It's soft.
从1,2,﹣3三个数中,随机抽取两个数相乘,积是正数的概率是( )
设x-b8=b0+b1x+b2x2+⋯+b8x8,如果b5+b8=-6,则实数b的值为( )