1a)25+27+(-25) b)36+(6-10) c)125-(65-4^3)^2020.2019+81:3^4 3a)3x-12=15 b)45-(x-12)=35 c)x-3=-4 d)26-x+|-13| e)28+2x=38 f)56-2.x^3=2

0 bình luận về “1a)25+27+(-25) b)36+(6-10) c)125-(65-4^3)^2020.2019+81:3^4 3a)3x-12=15 b)45-(x-12)=35 c)x-3=-4 d)26-x+|-13| e)28+2x=38 f)56-2.x^3=2”

1. Bài 1:

   a)25+27+(-25)

   =[25+(-25)]+27

   =0+27

   =27

   b)36+(6-10)

   =36+(-4)

   =+(36-4)

   =32

   Bài 3:

   a)3x-12=15

   ⇔3x=15+12

   ⇔3x=27

   ⇔x=27:3

   ⇔x=9

   b)45-(x-12)=35

   ⇔x-12=45-35

   ⇔x-12=10

   ⇔x=10+12

   ⇔x=22

   c)x-3=-4

   ⇔x=-4+3

   ⇔x=-(4-3)

   ⇔x=-1

   d)26-x=|-13|

   ⇔26-x=13

   ⇔x=26-13

   ⇔x=13

   e)28+2x=38

   ⇔2x=38-28

   ⇔2x=10

   ⇔x=10:2

   ⇔x=5

   f)56-2.$x^{3}$=2

   ⇔2.$x^{3}$=56-2

   ⇔2.$x^{3}$=54 

   ⇔$x^{3}$=54:2

   ⇔$x^{3}$=27

   ⇔$x^{3}$= $3^{3}$

   ⇔ x=3

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