Question

phân tích đa thức thành NT

y^4+2y^3+6y-9

Answer 1

y⁴ + 2y³ + 6y - 9

= y⁴ - y³ + 3y³ - 3y + 9y - 9

= y³ (y - 1) + 3y(y² - 1) + 9(y - 1)

= y³ (y - 1) + 3y(y - 1)(y + 1) + 9(y - 1)

= (y - 1) (y³ + 3y² + 3y + 9)

= (y - 1) [y²(y + 3) + 3(y + 3)]

= (y - 1)(y + 3)(y² + 3)

Chúc bạn học tốt!

Answer 2

y\(^4\)+2y\(^3\)+6y-9

=(y\(^2\))\(^2\)+2y\(^2\)y+y\(^2\)-[y\(^2\)-2.3y+(3y)\(^2\)]

=(y\(^2\)+y)\(^2\)-(y-3y)\(^2\)

=y\(^2\)(y+1)\(^2\)+4y\(^2\)

=y\(^2\)(y\(^2\)+2y+5)