Toán Lớp 5: Tìm x: a, x-7 4/5=9 7/15 b, 1/2:3-x=1 2/3 c, 3/4:x-1/3=2 2/3 d, x:3/4=3 1/3×2 1/4

Question

Toán Lớp 5:  Tìm x:  a, x-7  4/5=9  7/15 b, 1/2:3-x=1  2/3 c, 3/4:x-1/3=2  2/3 d, x:3/4=3  1/3×2  1/4

ngoclanhoa · Answer

a) x-7 4/5=9 7/15     =>x-39/5=142/15     =>x-117/15=142/15     =>x=142/15+117/15     =>x=259/15     b) 1/2:3-x=1 2/3     =>1/2:3/1-x=5/3     =>1/2&times;1/3-x=5/3     =>1/6-x=5/3     =>x=1/6-5/3     =>x=1/6-10/6     =>x=-9/6     =>x=-3/2     c) 3/4:x-1/3=2 2/3     =>3/4:x=8/3+1/3     =>3/4:x=9/3     =>x=3/4:9/3     =>x=3/4&times;3/9     =>x=9/36     =>x=1/4     d)x:3/4=3 1/3&times;2 1/4     =>x:3/4=10/3&times;9/4     =>x:3/4=90/12     =>x:3/4=15/2     =>x=15/2&times;3/4     =>x=45/8

hoaiphuong85 · Answer

a)   x - 7 4/5 = 9 7/15     x = 9 7/15 + 7 4/5    x = 17 4/15      b)   1/2 : 3 - x = 1 2/3     1/6 - x = 5/3     x = 1/6 - 5/3     x = (-3)/2       c)   3/4 : x - 1/3 = 2 2/3     3/4 : x = 2 2/3 + 1/3     3/4 : x = 3     x = 3/4 : 3     x = 1/4       d)   x : 3/4 = 3 1/3 xx 2 1/4     x : 3/4 = 15/2     x = 15/2 xx 3/4     x = 45/8