Question

Phân tích đa thức thành nhân tử y^2 + 5y - 20

Answer 1

Vô tỉ hả giết luôn!

\(y^2+5y-20=y^2+2,5y+2,5y+6,25-26,25\)

\(=\left(y+2,5\right)^2-\left(\sqrt{26,25}\right)^2\)

\(=\left(y+2,5-\sqrt{26,25}\right)\left(y+2,5+\sqrt{26,25}\right)\)

Chúc bạn học tốt!!!

Answer 2

\(y^2+5y-20=y^2+5y+6,25-26,25\)

\(=\left(y+2,5\right)^2-\left(\dfrac{\sqrt{105}}{2}\right)^2=\left(y+2,5-\dfrac{\sqrt{105}}{2}\right)\left(y+2,5+\dfrac{\sqrt{105}}{2}\right)\)

Answer 3

\(y^2+5y-20\)

=\(y^2+5y+6,25-26,25=(y+2,5)^2-(√26,25)^2\)

=\(\left(y+2,5-\text{√26,25}\right)\left(y+2,5+\text{√26,25}\right)\)