Question

\(5a^2-5b^2-20a+20 \)

phân tích đa thức thành nhân tử

Answer 1

\(5a^2-5b^2-20a+20b\)

\(=5\left(a^2-b^2\right)-20\left(a-b\right)\)

\(=5\left(a-b\right)\left(a+b\right)-20\left(a-b\right)\)

\(=\left[5\left(a+b\right)-20\right]\left(a-b\right)\)

\(=\left(5a+5b-20\right)\left(a-b\right)\)

Answer 2

\(5a^2-5b^2-20a+20=-5.\left(b-a+2\right).\left(b+a-2\right)\)