Сократите дробь: (a^2+2a-15)/(a^2-7a+12).

\[a^{2} + 2a - 15 = 0\]

\[a_{1} + a_{2} = - 2;\ \ a_{1} \cdot a_{2} = - 15\]

\[a_{1} = 3,\ \ a_{2} = - 5\]

\[a^{2} + 2a - 15 = (a - 3)(a + 5).\]

\[a^{2} - 7a + 12 = 0\]

\[a_{1} + a_{2} = 7;\ \ a_{1} \cdot a_{2} = 12\]

\[a_{1} = 4,\ \ a_{2} = 3\]

\[a² - 7a + 12 = (a - 4)(a - 3).\]