Question

rút gọn: A=2x^2(3x+4)(3x-4)_9/2(2x^2+1)(2x^2-1)

Answer 1

\(A=2x^2\left(3x+4\right)\left(3x-4\right)-\dfrac{9}{2}\left(2x^2+1\right)\left(2x^2-1\right)\)

\(=2x^2\left(9x^2-16\right)-\dfrac{9}{2}\left(4x^4-1\right)\)

\(18x^4-32x^2-18x^4+\dfrac{9}{2}\\ =-32x^2+\dfrac{9}{2}\)

Answer 2

Ta có: \(A=2x^2\left(3x+4\right)\left(3x-4\right)-\dfrac{9}{2}\left(2x^2+1\right)\left(2x^2-1\right)\)

\(=2x^2\left(9x^2-16\right)-\dfrac{9}{2}\left(4x^4-1\right)\)

\(=18x^4-36x^2-18x^4+\dfrac{9}{2}\)

\(=-36x^2+\dfrac{9}{2}\)