\(a,\left(3x+7\right)\left(2x+3\right)-\left(3x-5\right)\left(2x+11\right)\\ =\left(6x^2+14x+9x+21\right)-\left(6x^2-10x+33x-55\right)\\ =\left(6x^2+23x+21\right)-\left(6x^2+23x-55\right)\\ =6x^2+23x+21-6x^2-23x+55\\ =76\)
Vậy ...
\(b,\left(3x^2-2x+1\right)\left(x^2+2x+3\right)-4x\left(x^2-1\right)-3x^2\left(x^2+2\right)\\ =3x^4-2x^3+x^2+6x^3-4x^2+2x+9x^2-6x+3-4x^3+4x-3x^4-6x^2\\ =3\)
Vậy ...
`a)`\(\left(3x+7\right)\left(2x+3\right)-\left(3x-5\right)\left(2x+11\right)\)
\(=6x^2+9x+14x+21-6x^2-33x+10x+55\)
\(=76\) ( ko phụ thuộc vào biến )
`b)`\(\left(3x^2-2x+1\right)\left(x^2+2x+3\right)-4x\left(x^2-1\right)-3x^2\left(x^2+2\right)\)
\(=3x^4+6x^3+9x^2-2x^3-4x^2-6x+x^2+2x+3-4x^3+4x-3x^4-6x^2\)
\(=3\) ( ko phụ thuộc vào biến )
