Question

решите уравнения
а)(m+1)!(m-1)!= 30
b)(k+3)!(k+1)!=42
c) (m+5)!(m+3)!=56

Answer 1

a)
$m(m+1)=30$
$m^{2} +m-30=0$
$m_{1} =-6$
$m_{2} =5$
b)
$(k+2)(k+3)=42$
$k^{2} +5k+6-42=0$
$k^{2} +5k-36=0$
$k_{1} =-9$
$k_{2} =4$
c)
$(m+4)(m+5)=56$
$m^{2} +9m+20-56=0$
$m^{2} +9m-36=0$
$m_{1}=-12$
$m_{2} =3$