Сократите дробь 1)4-x^2/10-5x 2)x^6+x^4/x^4+x^2 3)b^7-b^10/b^9-b^3 /-дробь,^-степень...

1) $\frac{4- x^{2} }{10-5x}= \frac{2^{2}- x^{2} }{5(2-x)}= \frac{(2-x)(2+x)}{5(2-x)}= \frac{2+x}{5}$
2) $\frac{ x^{6}+ x^{4} }{ x^{4}+ x^{2}} = \frac{ x^{4}( x^{2} +1) }{ x^{2} ( x^{2} +1)} = \frac{ x^{4} }{ x^{2} } = x^{2}$
3) $\frac{ b^{7}-b^{10}}{b^{9}-b^{3}}= \frac{b^{3}(b^{4}-b^{7})}{b^{3}(b^{6}-1)}= \frac{-b^{4}(b^{3}-1)}{(b^{3})^{2} - 1^{2} } = \frac{-b^{4}(b^{3}-1)}{(b^{3}-1)(b^{3}+1)}= \frac{-b^{4}}{b^{3}+1}$