Bạn tham khảo tại https://books.google.com.vn/books?id=EHpTI8yrM04C&pg=PA26&lpg=PA26&dq=x4%2B9x-1)(3x2%2B2x-2)%3D0&source=bl&ots=z4-KX-Jdlk&sig=ACfU3U1MO5yKPj4GTF41zcv9RmsqsL8-FQ&hl=vi&sa=X&ved=2ahUKEwik-da6qpHoAhXiy4sBHdVtBGMQ6AEwAHoECAYQAQ#v=onepage&q=x4%2B9x-1)(3x2%2B2x-2)%3D0&f=false
~~~Learn Well Đõ Phương Thảo~~~