125: (2\(x\) - 3\(x\)) = 5⁵: 5³

  125: (-\(x\))  = 25

           \(x\)    = - 125 : 25

           \(x\)    = - 5

7x + 5x = 156

(7+5) x =156

12x = 156

x=156:12

x=13

(7+5)NHÂN X=156

    12 nhân X =156

            X      =156:12

            X      = 13

3/1.4+3/4.7+....+3/97.100

= 1-1/4+1/4-1/7+....+1/97-1/100

=1-1/100

=99/100

 (26 + 53 ) +(42 -26-55-53)

=79 + ( 16 -55 - 53 )

=79 + (-39-53)

=79 -39 - 53

=40 - 53 = -13

( 26 + 53 ) + ( 42 -26 - 55 - 53 )

= 79 + ( 16 - 55 - 53 )

= 79 + ( -39 - 53 )

= 79 + ( -92 )

= -13.

M.n ơi mk cần m.n giải gấp lắm nên cảm ơn m.n nhìu😊😊😊😊

a) 25 - 3x = 13

            3x = 25 - 13

            3x = 12

              x = 12 : 3

              x = 4

b) 13 + 3(130 - 3x) = 313

            3(130 - 3x) = 313 - 13

            3(130 - 3x) = 300

               130 - 3x = 300 : 3

               130 - 3x = 100

                         3x = 130 - 100

                         3x = 30

                           x = 30 : 3

                           x = 10

125 ^o/_o : x + 234 = 7,75

1,25 : x + 234 = 7,75 

1,25 : x           =7,75 - 234

1,25 : x           =-226,25 

          x           =1,25 : (-226,25)

          x           =

nhầm

a, ( - 125 ) + 100 + 80 + 125 + 20

= ( - 125 + 125 ) + 100 + ( 80 + 20 )

= 0 + 100 + 100

= 200

b, 27 + 55 + ( - 17 ) + ( - 55 )

= ( 27 - 17 ) + ( 55 - 55 )

= 10 + 0 

= 10

c, ( - 92 ) + ( - 251 ) + ( - 8 ) + 251 

= ( - 92 - 8 ) + ( - 251 + 251 )

= - 100 + 0

= - 100

d, ( - 31 ) + ( - 95 ) + 131 + ( - 5 )

= ( - 31 + 131 ) + ( - 95 - 5 )

= 100 + ( - 100 )

= 0

a) (-125) + 100 + 80 + 125 + 20

= [(-125) + 125] + 100 + (80 + 20)

= 0 + 100 + 100

= 200

b) 27 + 55 + (-17) + (-55)

= [27 + (-17)] + [55 + (-55)]

= 10 + 0

= 10

c) (-92) + (-251) + (-8) + 251

= [(-92) + (-8)] + [(-251) + 251]

= (-100) + 0

= -100

d) (-31) + (-95) + 131 + (-5)

= [(-31) + 131] + [(-95) + (-5)]

= 100 + (-100)
= 0

\(a,-81.46-81.55+81\)

\(=81.\left(-46\right)-81.55+81\)

\(=81.\left(-46-55+1\right)\)

\(=81.\left(-100\right)\)

\(=-8100\)

\(b,35.\left(17-5\right)-17.\left(35-5\right)\)

\(=35.17-35.5-17.35+17.5\)

\(=\left(35.17-17.35\right)-\left(35.5-17.5\right)\)

\(=35.\left(17-17\right)-5.\left(35-17\right)\)

\(=35.0-5.18\)

\(=0-90\)

\(=-90\)

Cách 2 : \(35.\left(17-5\right)-17.\left(35-5\right)\)

\(=35.12-17.30\)

\(=420-510\)

\(=-90\)

\(c,-125.6.\left(-8\right).\left(-50\right)\)

\(=\left(-125\right).\left(-8\right).6.\left(-50\right)\)

\(=1000.\left(-300\right)\)

\(=-300000\)