Question

- X^2 + 9x -21+x²-5x+1=​

Answer 1

$-x^{2} + 9x -21+x^{2} -5x+1=\\= -x^{2} +x^{2} + 9x-5x-21+1\\=9x-5x-21-1\\=4x-21-1\\=4x-22$

Espero que te sirva de ayuda :)