a)25% x m + 3/4 x m=30 b)m=2017 – 2016 + 2015 – 2014 + 2013 – 2012 + 2011 – 2010

Đáp án:

a.

`25% × m + 3/4 × m = 30`

`1/4 × m + 3/4 × m = 30`

`(1/4 + 3/4) × m = 30`

`1 × m = 30`

`m = 30 : 1`

`m = 30`

Vậy `m = 30`

b.

`m = 2017 – 2016 + 2015 – 2014 + 2013 – 2012 + 2011 – 2010`

`m = (2017 – 2016) + (2015 – 2014) + (2013 – 2012) + (2011 – 2010)`

`m = 1 + 1 + 1 + 1`

`m = 4`

Vậy `m = 4`