Question

Скоротить дріб z²-49 z²+14z+49 '​

Answer 1

$\displaystyle\bf\\\frac{z^{2}-49 }{z^{2} +14z+49} = \frac{z^{2}-7^{2} }{z^{2} +2\cdot z\cdot 7+7^{2} } =\frac{(z-7)\cdot(z+7)}{(z+7)^{2} } =\frac{z-7}{z+7}$

Answer 2

(z²-49)/(z²+14z+49)=(z²-7²)/(z²+2*z*7+7²)=(z-7)*(z+7)/(z+7)²=(z-7)/(z+7)