Toán Lớp 8: Giải phg trình
a, $\frac{x+29}{31}$ – $\frac{x+27}{33}$ = $\frac{x+17}{43}$ – $\frac{x+15}{45}$
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Toán Lớp 8: Giải phg trình
a, $\frac{x+29}{31}$ – $\frac{x+27}{33}$ = $\frac{x+17}{43}$ – $\frac{x+15}{45}$
Comments ( 1 )
(x+29)/31-(x+27)/33=(x+17)/43-(x+15)/45
<=>((x+29)/31+1)-((x+27)/33+1)=((x+17)/43+1)-((x+15)/45+1)
<=>((x+29)/31+1/1)-((x+27)/33+1/1)=((x+17)/43+1/1)-((x+15)/45+1/1)
<=>((x+29)/31+31/31)-((x+27)/33+33/33)=((x+17)/43+43/43)-((x+15)/45+45/45)
<=>((x+29+31)/31)-((x+27+33)/33)=((x+17+43)/43)-((x+15+45)/45)
<=>(x+60)/31-(x+60)/33=(x+60)/43-(x+60)/45
<=>(x+60)/31-(x+60)/33-(x+60)/43+(x+60)/45=0
<=>(x+60).(1/31-1/33-1/43+1/45)=0
<=>x+60=0
<=>x=0-60
<=>x=-60
Vậy, S={-60}