ko làm tắt nha Tìm x biết: 13+(x-6)=15 25+(-2+x)=5 30+(32-x)=10 -30+(25-x)=-1 5-(4-x)=6 -26-(x-7)=0 (5-x)-7=-15 3-(17-x)=-12

`13 + ( x - 6 ) = 15`

`⇔ 13 + x - 6 = 15`

`⇔ x = 15 - 13 + 6`

`⇔ x = 8`

`_`

`25 + ( -2 + x ) = 5`

`⇔ 25 - 2 + x = 5`

`⇔ x = 5 - 25 + 2`

`⇔ x = -18`

`_`

`30 + ( 32 - x ) = 10`

`⇔ 30 + 32 - x = 10`

`⇔ -x = 10 - 30 - 32`

`⇔ -x = -52`

`⇔ x = 52`

`_`

`-30 + ( 25 - x ) = -1`

`⇔ -30 + 25 - x = -1`

`⇔ -x = -1 + 30 - 15`

`⇔ -x = 14`

`⇔ x = -14`

`_`

`5 - ( 4 - x ) = 6`

`⇔ 5 - 4 + x = 6`

`⇔ x = 6 - 5 + 4`

`⇔ x = 5`

`_ `

`-26 - ( x - 7 ) = 0`

`⇔ -26 - x + 7 = 0`

`⇔ -x = 0 + 26 - 7`

`⇔ -x = 19`

`⇔ x = -19`

`_`

`( 5 - x ) - 7 = -15`

`⇔ 5 - x - 7 = -15`

`⇔ -x = -15 - 5 + 7`

`⇔ -x = -13`

`⇔ x = 13`

`_`

`3 - ( 17 - x ) = -12`

`⇔ 3 - 17 + x = - 12`

`⇔ x = -12 - 3 + 17`

`⇔ x = 2`