Question

Tính giá trị biểu thức :

a, 3/4 + 1/2 x 7/2                 b, 6/15 - 1/3 : 5/3

c, x - 4/9 = 3/7 : 9/4             d, 7/9 x 3/5 - 1/2 = 1/5

Answer 1

`a, 3/4 + 1/2 xx 7/2`

`= 3/4 + 7/4`

`=10/4`

`=5/2`

`b, 6/15 - 1/3 : 5/3`

`= 6/15 - 1/3 xx 3/5`

`= 6/15 - 3/15`

`= 3/15`

`=1/5`

`c, x-4/9 = 3/7 : 9/4`

`=> x-4/9= 3/7 xx 4/9`

`=> x-4/9= 12/63`

`=> x-4/9=4/21`

`=> x= 4/21 +4/9`

`=>x= 40/63`

`d, 7/9 xx 3/5 -1/2=1/5`

`->` sao lại bằng có `x` ko vậy ạ?

Answer 2

`a,`

`3/4+1/2 \times 7/2=3/4+7/4=10/4=5/2`

`b,`

`6/15 - 1/3 \div 5/3=6/15-1/5=1/5`

`c,` Tìm x?

`x-4/9=3/7 \div 9/4`

`x-4/9=4/21`

`x=4/21+4/9`

`x=40/63`

`d, 7/9x \times 3/5-1/2=1/5`

`7/9x \times 3/5=1/5+1/2`

`7/9x \times 3/5=7/10`

`7/9x=7/10 \div 3/5`

`7/9x=7/6`

`x=7/6 \div 7/9=3/2`

Answer 3

  

Answer 4

Câu c toi ghi nhầm  là : 5/7 : 9/14 - 17/18

Answer 5

`[` Tớ bổ sung `]`

`5/7 : 9/14 - 17/18`

`= 5/7 xx 14/9 - 17/18`

`= 70/63 - 17/18`

`=10/9-17/18`

`= 20/18-17/18`

`= 3/18`

`=1/6`

Answer 6

$a,$

$3/4+1/2\times 7/2=3/4+7/4=10/4=5/2$

$b,$

$6/15-1/3÷5/3=6/15-1/5=1/5$

$c,$ Tìm x?

$x-4/9=3/7÷9/4$

$x-4/9=4/21$

$x=4/21+4/9$

$x=40/63$

$d,7/9x\times 3/5-1/2=1/5$

$7/9x\times 3/5=1/5+1/2$

$7/9x\times 3/5=7/10$

$7/9x=7/10÷3/5$

$7/9x=7/6$

$x=7/6÷7/9=3/2$