a) 2x-30=-14

2x=(-14)+30

2x=16

x=16:2

x=8

b) 230-4*(x+5)=30

4*(x+5)=230-30

4*(x+5)=200

x+5=200:4

x+5= 50

x=50-5

x=45

500 - (-300) -(-230)+(-3)^3-1 ^ 2016

=    800 + 230 + (-27) - 1

=    1030 + (-27) -1

=  1003 -1

=  1002

500-[(-300)-(-230)+(-3)³-1

=500 -(-73)^3-1

=500 + 389016

=389516

 20 + 30 + (-20) + (-30) = 100

100 + 230 + 600 + (-100) + (-230) = 600

  20+30+(-20)+(-30)+100

=[20+(-20)]+[30+(-30)]+100

=0+0+100

=100.

  100+230+600+(-100)+(-230)

=[100+(-100)]+[230+(-230)]+600

=0+0+600

=600.

20 + 30 +(- 20) + (-30 )+100=20 +(-20)+30 +(-30)+ 100=0 +0+100=100

100+230+600+(-100)+(-230)=100+(-100)+230+(-230)+600=0+0+600=600

500 × 4 × 2 × 25 - 500 × 3 × 2 × 30

= 500 × (4 × 2 × 25) - 500 × (3 × 2 × 30)

= 500 × 200 - 500 × 180

= 500 × (200 - 180)

= 500 × 20

= 10000

x + 19,34 = 42,6 

x = 23,26 

b. x - 230 = 244,86 

x = 474,86 

c. x = 1,56 x 58,2 = 90,792

d. x = 200 : 12,3 = 200/12,3 

e. 34,8 : x = 1,25 => x = 27,84

Ra luôn kết quả để bạn soát lại:
\(1/\)\(x=23,26\)
\(2/\)\(x=474,86\)
\(3/x=90,792\)
\(4/x=16,2601...\)
\(5/x=27,84\)

60×20×30×40+500

120×30×40+500

3600×40+500

144000+500

144500

Trả lời 

\(20\times30\times20\times30\times40+500\)

\(=600\times600\times40+500\)

\(=360000\times40+500\)

\(=14400000+500\)

\(=14400500\)

14400500

a) x - 1845 = 115 x 2 - 25 x 3

x - 1845 = 230 - 75

x - 1845 = 155

x = 155 + 1845

\(b,230+35x4=x+\frac{700}{5}+30\)

230 + 140 = x + 140 + 30

370 = x + 170

x = 370 - 170

x = 200

a) x - 1845 = 115 x 2 - 25 x 3

x - 1845 = 230 - 75

x - 1845 = 155

x            = 155 + 1845

x            = 2000

          Vậy x = 2000

b) 230 + 35 x 4 = x + 700 / 5+30

    370               = x + 140 + 30

    370               = x + 170

    x                   = 370 - 170

    x                   = 200

             Vậy x = 200

a)  x - 1845 = 115 x 2 - 25 x 3

=> x =  230 - 75 + 1845

=> x = 155 + 1845

=> x = 2000

b)  230 + 35 x 4=x + 700/5 + 30

=> 230 + 140 = x + 700/5 + 30

=> x + 700/5 + 30 = 370

=> x + 700/5 = 340

=> x + 140 = 340

=> x = 340 - 140

=> x = 200

chúc bạn học tốt !

a) y : 0,25 + y x 8 - y : 0,5 = 230

y x 4 + y x 8 - y x 2 = 230

y x (4 + 8 - 2) = 230

y x 10 = 230

y = 230 : 10

y = 23

b) \(x\) x 4 + \(x\) x 6 = 30

\(x\) x (4 + 6) = 30

\(x\) x 10 = 30

\(x\) = 30 : 10

\(x\) = 3

a; y :0,25 + y x 8 - y: 0,5 = 230

    y x 4 + y x 8 - y x 2 = 230

    y x (4 + 8 - 2) = 230

    y x 10 = 230

     y = 230 : 10

     y = 23

b; \(x\) \(\times\) 4 + \(x\) \(\times\) 6 = 30

    \(x\) \(\times\) (4 + 6) = 30

     \(x\) \(\times\) 10 = 30

     \(x\)           = 30 : 10

      \(x\)          = 3