Toán Lớp 4: Tìm x: a) X+ 2/5: 3/4=1 b) X+ 3/7-2/5= 3/10 c) 7/3 -X ×2/5= 3/10 d)3/7 +X :2/5 =5/4

Question

Toán Lớp 4:  Tìm x: a) X+ 2/5: 3/4=1      b) X+ 3/7-2/5= 3/10 c) 7/3 -X ×2/5= 3/10     d)3/7 +X :2/5 =5/4

phuongthaongoc · Answer

Giải đáp + Lời giải và giải thích chi tiết:   a, x + 2/5 : 3/4 = 1   x  + 2/5 = 1 xx 3/4   x + 2/5 = 3/4   x = 3/4 - 2/5   x = 7/20   b, x + 3/7 - 2/5 = 3/10    x + 3/7 = 3/10 + 2/5   x + 3/7 = 7/10   x = 7/10 - 3/7   x = 19/70   c, 7/3 - x xx 2/5 = 3/10   x xx 2/5 = 7/3 - 3/10   x xx 2/5 = 61/10   x = 61/20 : 2/5   x = 61/12   d, 3/7 + x : 2/5 =5/4   x : 2/5 = 5/4 - 3/7   x : 2/5 = 23/28   x = 23/28 xx 2/5   x = 23/70

thienthanh · Answer

a, x + 2/5 : 3/4 = 1    x + 2/5 . 4/3 = 1    x + 8/15 = 1    x= 1 - 8/15    x= 7/15   $ text{Vậy}$  x= 7/15   -------------------   b, x + 3/7 - 2/5 = 3/10    x + 3/7= 3/10 + 2/5    x + 3/7= 7/10    x= 7/10 - 3/7    x= 19/70   $ text{Vậy}$  x= 19/70   ----------------------   c, 7/3 - x  times 2/5 = 3/10    x  times 2/5 = 7/3 - 3/10    x  times 2/5 = 61/30    x = 61/30 : 2/5    x = 61/30 . 5/2    x = 61/12   $ text{Vậy}$  x = 61/12   -------------------------   d, 3/7 + x : 2/5 = 5/4   x : 2/5 = 5/4 - 3/7   x : 2/5 = 23/28   x= 23/28 . 2/5   x= 23/70   $ text{Vậy}$ x= 23/70