\(A\left(x\right)-B\left(x\right)=\left(6x^2+11+3x\right)-\left(-2+4x-7x^2\right)\)
\(=6x^2+11+3x+2-4x+7x^2\)
\(=13x^2-x+13\)
\(A\left(x\right)+B\left(x\right)=6x^2+11+3x-2+4x-7x^2\)
\(=-x^2+7x+9\)
`A(x) +B(x)= (6x^2 +11+3x)+(-2+4x-7x^2)`
`= 6x^2 +11+3x+ (-2)+4x-7x^2`
`= -x^2 +7x + 9`
`A(x) -B(x)= (6x^2 +11+3x)-(-2+4x-7x^2)`
`= 6x^2 +11+3x +2 -4x+7x^2`
`=13x^2 -x+13`
\(A\left(x\right)+B\left(x\right)=\left(6x^2+11+3x\right)+\left(-2+4x-7x^2\right)\)
\(=6x^2+11+3x-2+4x-7x^2\)
\(=-x^2+7x+9\)
- Hệ số cao nhất: \(9\)
\(A\left(x\right)-B\left(x\right)=\left(6x^2+11+3x\right)-\left(-2+4x-7x^2\right)\)
\(=6x^2+11+3x+2-4x+7x^2\)
\(=13x^2-x+13\)
- Hệ số cao nhất: \(13\)
