\(\left(x+5\right)+\left(x+10\right)+...+\left(x+60\right)=474\\ \Rightarrow\left(x+x+...+x\right)+\left(5+10+...+60\right)=474\\ \Rightarrow12x+390=474\\ \Rightarrow12x=84\\ \Rightarrow x=7\)

\(\left(x+5\right)+\left(x+10\right)+...+\left(x+60\right)=474\\ \left(x+x+...+x\right)+\left(\dfrac{\left(60+5\right)\left[\left(60-5\right):5+1\right]}{2}\right)=474\\ 12x+390=474\\ 12x=474-390\\ 12x=84\\ x=84:12\\ x=7\)

\(\left(x+5\right)+\left(x+10\right)+...+\left(x+60\right)=474\)

\(\left(x+x+...+x\right)+\left(\frac{\left(60+5\right)\left[\left(60-5\right):5+1\right]}{2}\right)=474\)

\(12x+390=474\)

\(12x=84\)

\(x=7\)

\(\left(x+5\right)+\left(x+10\right)+\left(x+15\right)+...+\left(x+60\right)=474\)

\(x+5+x+10+x+15+...+x+60=474\)

\(x+x+x+...+x+5+10+15+...+60=474\)

12 số x

\(12\times x+\left(60+5\right)\times12\div2=474\)

\(12\times x+390=474\)

\(12\times x=474-390\)

\(12\times x=84\)

\(x=84\div12\)

\(x=7\)

Vậy \(x=7\).

(x+5)+(x+10)+(x+15)+....+(x+60)=450

         12.x + (5+10+....+60)         =450

             12.x +   390                   =450

                    12.x                        =450-390

                     12.x                       =  60

             =>         x = 60:12 =5

 194x6x5-10x60x3-68x15

=30x194-30x60-2x34x15

=30x194-30x60-30x34

30x(194-60-34)

=30x100

=3000

194 x 6  x 5 - 10 x 60 x 3 - 68 x 15

= 194 x 30 - 30 x 60 - 34 x 2 x15 

= 194 x 30 - 30 x 60 - 34 x 30

= 30 x ( 194 - 60 - 34 )

= 30 x 100 = 3000

194 x 6 x 5 - 10 x 60 x 3 - 68 x 15

= 194 x 30 - 60 x 30 - 34 x 2 x 15

= 194 x 30 - 60 x 30 - 34 x 30

= ( 194 - 60 - 34 ) x 30

= 100 x 30

= 3000

 (x+5)+(x+10)+(x+15)+.....+(x+60)=450. x+5+x+10+x+15+...+x+60=450. 12.x + (5+10+15+...+60)=450. 12.x + 390 = 450. ⇒12.x=60⇒x=5 ...

( x + 5 ) + ( x + 10 ) + ( x + 15 ) + .... + ( x + 60 ) = 450

x + 5 + x + 10 + x + 15 + ... + x + 60 = 450

12 . x + ( 5 + 10 + 15 + ... + 60 )

12 . x + 390 = 450

=> 12 . x = 450 - 390

=> 12 . x = 60

=>       x  = 60 : 12

=>       x  = 5

Vậy x = 5

bằng 5

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

-2x - 40 = (5 - x) - 45

-2x - 40 = -40 - x

-2x - x = 40 - 40

      -3x = 0

         x = 0

2(x - 4) - 3(x + 7) = 14

    2x - 8 - 3x - 21 = 14

                 -x - 29 = 14

                        -x = 14  + 29

                        -x = 43 

                         x = -43

-7(5 - x) - 2(x - 10) = 15

-35 + 7x - 2x + 20 = 15

              -15 + 5x = 15

                       5x = 15 + 15

                       5x = 30

                         x = 6

         \(-2x-40=\left(5-x\right)-\left(-15+60\right)\)

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

\(\Leftrightarrow\)\(-2x-40=-x-40\)

\(\Leftrightarrow\)\(-2x+x=40-40\)

\(\Leftrightarrow\)\(x=0\)

Vậy....

\(x+18=2-2x\)

\(2x+x=2-18\)

\(3x=-20\)

\(x=-20:3\)

\(x=\frac{-20}{3}\)

[(90-15xX)-8]x5+10=30

_____________=30-10

___________=20:5

_________=4+8

15xX=90-12

X=78:15

X=5.2

[(90-15x X)-8] x 5 + 10 = 60 x 0,5

[(90-15xX)-8] x 5 + 10 =  30

[(90-15xX)-8] x 5         =  30 - 10 = 20

(90-15xX)-8               =  20 : 5 = 4

90 - 15xX                   =  4 + 8 = 12

         15xX                 =  90-12

          15xX                 =  78

                X               =  78 : 15

                X                =   5,2

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