-2x-40=(5-x)-(-15+60)

=> -2x - 40 = 5 - x + 15 +60

=> -2x - 40 = 80 - x

=> -2x + x = 80 + 40

=> -x = 120

-2x-40=(5-x)-(-15+60)

-2x - 40 = 5 - x - 45

-2x - 40 = -x - 40

-2x + x = -40 + 40

-1x = 0

x = 0

(-25)-(5.x-3)=4

5.x-3 = -25 - 4

5.x-3=-29

5.x=-26

x=-26/5

x=-5,2

5.x-6=20-(12-6)

5.x-6=20-6

5.x-6=14

5.x=20

x=20:5

x=4

vậy x=4

1/
-25-(5x-3)=4
-25-4=5x-3
-25-4+3=5x
5x= -26
x= -26/5
2/
5x-6=20-(12-6)
5x = 20-12+6+6
5x = 20
x = 20/5 = 4
3/
-2x -40 = (5-x) -(-15+60
-2x -40 = 5-x +15-60
-2x +x = 5+15-60+40
-x = 0
x=0

-2x-40=(5-x)-(-15+60)

-2x-40=5-x+15-60

-2x-40=5+15-60-x

-2x-40=-40-x

-2x=x

TH1:x=0 thì -2x0=0(chọn)

TH2:x>0 thì -2x<0 mà x>0(loại)

TH3:x<0 thì -2x>0 mà x<0(loại)

Vậy x=0

2 x + 5 = 15 

2x        = 15 - 5 

 x         = 10 : 2 

 x         = 5

2x + 5 = 15 

      2x = 15 - 5

      2x = 10

        x = 10 : 2 

        x = 5

2 x + 5 = 15

2 x       = 15 - 5

x          = 10 : 2 

x          = 5

3.5^x=60.5⁸+15.25⁴

=>3.5^x=12.5.5⁸+3.5.(5²)⁴

=>3.5^x=12.5⁹+3.5⁹

=>3.5^x=(12+3).5¹⁹

=>3.5 ^x=15.5⁹=3.5.5⁹

=>3.5^x=3.5¹⁰

=> x=10

Tk mk

3.5^x=60.5⁸+15.25⁴

=> 3.5^x=60.5⁸+15.(5²)⁴

=>3.5^x=60.5⁸+15.5⁸

=>3.5^x=5⁸.(60+15)

=>3.5^x=5⁸.75

=>3.5^x=5⁸ . 25.3(75=25..3)

=>3.5^x=5⁸.5².3

=>3.5^x=5¹⁰.3

=> x=10

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