Đáp án + Giải thích các bước giải:
7) 4/5 + 5/7 : x = 17/10 8) 4/5 + 5/7 : x = 1
5/7 : x = 4/5 - 17/10 5/7 : x = 4/5 - 1
5/7 : x = -9/10 5/7 : x = -1/5
x = 5/7 : -9/10 x = 5/7 : -1/5
Vậy x = -25/23 Vậy x = -25/7
9) (1/2 - 1/4) x X = 28/3 x (1/4 - 1/8) 10) (2/11 + 1/3) x X = (1/7 - 1/8) x 56
1/4 x X = 28/3 x 1/8 17/33 x X = 1/56 x 56
1/4 x X = 7/6 17/33 x X = 56/56
X = 7/6 : 1/4 17/33 x X = 56/56 : 17/33
Vậy X = 14/3 Vậy X = 308/157
11) 7/2 - (x + 1/3) = 5/2 12) 3/35 + (3/5 + x) = 2/7
x + 1/3 = 7/2 - 5/2 3/5 + x = 3/35 - 2/7
x + 1/3 = 1 3/5 + x = -1/5
x = 1 - 1/3 x = 3/5 + -1/5
Vậy x = 2/3 Vậy x = 2/5
13) 11/12 - (2/5 + x) = 2/3 14) X x (1/5 + 1/4) - (1/7 - 1/8) = 0
2/5 + x = 11/12 - 2/3 X x 9/20 - 1/56 = 0
2/5 + x = 1/4 X x 9/20 = 0 + 1/56
x = 1/4 - 2/5 X x 9/20 = 1/56
Vậy x = -3/20 X = 1/56 : 9/20
Vậy X = 5/126
Mk ko gõ đc phân số, mong bạn thông cảm!
