Question

Answer 1

\(a,A:B=\left(15x^3+7x^2+12x+a\right):\left(x-2\right)\\ =\left(15x^3-30x^2+37x^2-74x+86x-172+172+a\right):\left(x-2\right)\\ =\left[15x^2\left(x-2\right)+37x\left(x-2\right)+86\left(x-2\right)+a+172\right]:\left(x-2\right)\\ =15x^2+37x+86\left(\text{dư }a+172\right)\\ b,A⋮B\Leftrightarrow a+172=0\Leftrightarrow a=-172\)