Question

(9-x^2)(x^2-16)/(x^2-7x+12) сократить дробь

Answer 1

$\frac{(9-x^2)(x^2-16)}{(x^2-7x+12)}\\\frac{(3-x)(3+x)(x-4)(x+4)}{(x^2-4x-3x+12)}=\frac{(3-x)(3+x)(x-4)(x+4)}{(x(x-4)+3(x-4)}=\frac{(3-x)(3+x)(x-4)(x+4)}{(x-4)(x+3)}=\\(3-x)(x+4)=3x+12-x^2-4x=12-x^2-x$