Toán Lớp 7: Tìm x biết (x+2)/238x+3)/237+(x+4)/236+(x+5)/235=4

Question

Toán Lớp 7:  Tìm x biết (x+2)/238x+3)/237+(x+4)/236+(x+5)/235=4

tuenhioanh · Answer

$ displaystyle  begin{array}{{>{ displaystyle}l}}  frac{x+2}{238} + frac{x+3}{237} + frac{x+4}{236} + frac{x+5}{235} =-4    frac{x+2}{238} +1+ frac{x+3}{237} +1+ frac{x+4}{236} +1+ frac{x+5}{235} +1=0    frac{x+240}{238} + frac{x+240}{237} + frac{x+240}{236} + frac{x+240}{235} =0     ( x+240) left( frac{1}{238} + frac{1}{236} + frac{1}{235} right) =0      rightarrow x=-240   end{array}$     Đề sau dấu = l&agrave; trừ 4 hợp l&iacute; hơn đ&oacute;

quynhmaithu · Answer

#huy   (x+2)/238+(x+3)/237+(x+4)/236+(x+5)/235=4   =>(x+2)/238+1+(x+3)/237+1+(x+4)/236+1+(x+5)/235+1=0   =>(x+240)/238+(x+240)/237+(x+240)/236+(x+240)/235=0   =>(x+240).(1/238+1/237+1/236+1/235)=0   =>x=-240    sau dấu '=' l&agrave; 1 số l&agrave; số dương chuyển vế th&agrave;nh &acirc;m