Question

1.tìm x 

A.x-5/7-13/14=1.          B.x+x×1/3+x×1/6=13/6

2.Tính bằng cách thuận tiện nhất.

A.62,89+18,27+34,11

B.13,3÷18+30,7÷18

C.3/2×1/5+27/2×1/9+3/2×4/5

Giúp mik với

Answer 1

`1)`

`a,`

`x-5/7-13/14=1`

`=> x-5/7= 1 +13/14`

`=>  x-5/7=  14/14 +13/14`

`=>  x-5/7=  27/14`

`=> x= 27/14 + 5/7`

`=>x= 27/14 + 10/14`

`=>x= 37/14`

vậy `x=37/14`

`b,`

`x+x×1/3+x×1/6=13/6`

`=> 2x xx (1/3 + 1/6)=13/6`

`=> 2x xx ( 2/6 + 1/6)=13/6`

`=> 2x xx 3/6 = 13/6`

`=> 2x xx 2 = 13/6`

`=> 2x = 13/6 : 2`

`=> 2x = 13/6 xx 1/2`

`=> 2x = 13/12`

`=> x= 13/12 : 2`

`=> x= 13/12 xx 1/2`

`=> x= 13/24`

vậy `x=13/24`

`2)`

`62,89+18,27+34,11`

`= (62,89+34,11)+18,27`

`=97 + 18,27`

`= 115,27`

`---------`

`13,3:18+30,7:18`

`= (13,3 + 30,7):18`

`= 44 : 18`

`=44/18 = 22/9`

`--------`

`3/2×1/5+27/2×1/9+3/2×4/5`

`= 3/2 xx ( 1/5 + 4/5) xx ( 27/2 +3/2) xx 1/9`

`= 3/2 xx 1 xx 30/2 xx 1/9`

`=  3/2 xx 15xx 1/9`

`= 45/2 xx 1/9`

`= 45/18`

`=45/18`