Môn Toán Lớp 7: tìm x c, 5/7 - 1/13 0,25=7/2-x d, -4/7 . x 7/5=1/8:(-5/3)

Question

Môn Toán Lớp 7:  tìm x c, 5/7 - 1/13 +0,25=7/2-x                    d, -4/7  . x +7/5=1/8:(-5/3)

kimoanh34 · Answer

Giải đáp:    c)   rac{5}{7}-rac{1}{13}+0,25=rac{7}{2}-x   => rac{5}{7}-rac{1}{13}+rac{1}{4}= rac{7}{2}-x   =>rac{260}{364}-rac{28}{364}+rac{91}{364}=rac{7}{2}-x   => rac{323}{364}=rac{7}{2}-x   => x= rac{7}{2}-rac{323}{364}   => x=rac{1274}{364}-rac{323}{364}   => x=rac{951}{364}   Vậy x=rac{951}{364}   d)   -rac{4}{7}.x+rac{7}{5}=rac{1}{8}:(-rac{5}{3})   => rac{-4}{7}.x+rac{7}{5}=rac{1}{8}.rac{-3}{5}   => rac{-4}{7}.x+rac{7}{5}=rac{-3}{40}   => rac{-4}{7}.x=rac{-3}{40}-rac{7}{5}   => rac{-4}{7}.x=rac{-3}{40}-rac{56}{40}   => rac{-4}{7}.x=rac{-59}{40}   => x=rac{-59}{40}.rac{-7}{4}   => x=rac{413}{160}   Vậy x=rac{413}{160}

kimnguenoanh · Answer

c) 5/7-1/13+0,25=7/2-x   260/364-28/364+91/364=1274/364-x   323/364=1274/364-x   x=1274/364-323/364   x=951/364   Vậy x=951/364   d) -4/7x+7/5=1/8:(-5/3)   -4/7x+7/5=1/8 .(-3/5)   -4/7x+56/40=-3/40   -4/7x=-3/40-56/40   -4/7x=-59/40   x=-59/40:(-4/7)   x=59/40 . 7/4   x=413/160   Vậy x=413/160

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Môn Toán Lớp 7: tìm x c, 5/7 – 1/13 +0,25=7/2-x d, -4/7 . x +7/5=1/8:(-5/3)

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