`78=2.3.13`

`120=2^3 . 3.5`

`196=2^2 . 7^2`

`-4,75 - 1 7/12`

`=-475/100 - 19/12`

`=-19/4 - 19/12`

`=-57/12 - 19/12`

`=-76/12`

`=-19/3`

`-9/12 - (-35/42)`

`=-9/12 - (-5/6)`

`=-3/4 + 5/6`

`=-9/12 + 10/12`

`=1/12`

`0,75 - 2 1/3`

`=75/100 - 7/3`

`=3/4 - 7/3`

`=9/12 - 28/12`

`=-19/12`

`-1 1/4 - (-2,25)`

`=-5/4 - (-225/100)`

`=-5/4 - (-9/4)`

`=-5/4 + 9/4`

`=4/4`

`=1`

`16.32 = 2^4 . 2^5 = 2`$^{4+5}$ `=2^9`

Áp dụng phép nhân của lũy thừa : `a^m . a^n = a`$^{m+n}$

`(x+6)^2 = 25`

`=>(x+6)^2 = 5^2 = -5^2`

`=>x+6=5` hoặc `x+6=-5`

`=>x=5-6` hoặc `x=-5-6`

`=>x=-1` hoặc `x=-11`

Vậy `x` $\in$ `{-11;-1}`