Question

Сократите дробь:
a)15-5y       б)m²-4mn+4n² 
   9-y²               m²-4n  

Answer 1

Сократим дробь:

а) $frac{15-5y}{9- y^{2} } = frac{5*(3-y)}{(3-y)(3+y)} = frac{5}{3+y}$

б) $frac{ m^{2} - 4mn + 4 n^{2} }{ m^{2} - 4n^{2}} = frac{(m)^{2} - 2*2nm + (2n)^{2}}{(m - 2n)(m+2n)} = frac{ (m - 2n)^{2} }{(m - 2n)(m+2n)} = frac{m-2n}{m+2n}$