Question

Thu gọn :

a) \(2\left(x^2-3x+5\right)-4\left(x^2+x-1\right)\)

b) \(-5\left(x^2-3\right)+2\left(x-5\right)-4\left(x^2+x-5\right)\)

c) \(\frac{1}{2}\left(2x^2-4x+1\right)-\left(x^2+\frac{1}{2}\right)\)

Answer 1

a ) \(2\left(x^2-3x+5\right)-4\left(x^2+x-1\right)\)

\(=2x^2-6x+10-4x^2-4x+4\)

\(=-2x^2-10x+14\)

b ) \(-5\left(x^2-3\right)+2\left(x-5\right)-4\left(x^2+x-5\right)\)

\(=-5x^2+15+2x-10-4x^2-4x+20\)

\(=-9x^2+25-2x\)

 

Answer 2

a)

\(2\left(x^2-3x+5\right)-4\left(x^2+x+1\right)\)

\(=2x^2-6x+10-4x^2-4x+4\)

\(=-2x^2-10x+14\)

b)

\(-5\left(x^2-3\right)+2\left(x-5\right)-4\left(x^2+x+5\right)\)

\(=-5x^2+15+2x-10-4x^2-4x+20\)

\(=-9x^2-25-2x\)

c)

\(\frac{1}{2}\left(2x^2-4x+1\right)-\left(x^2+\frac{1}{2}\right)\)

\(=x^2-2x+\frac{1}{2}-x^2-\frac{1}{2}\)

\(=-2x^2\)