Question

Tìm \(x\in N\), biết:

\(a\backslash\left(x-3\right):2=5^{14}:5^{12}\)

\(b\backslash4x+3x=30-20:10\)

\(c\backslash\left(x-28\right):12=5\)

\(d\backslash7x-2x=5^{69}:5^{67}\)

\(e\backslash1440:\left[120-\left(3x+9\right)\right]=120\)

Answer 1

\(a.\left(x-3\right):2=5^{14}:5^{12}\)

\(\left(x-3\right):2=5^2\)

\(\left(x-3\right):2=25\)

\(x-3=25\times2\)

\(x=50+3\)

\(x=53\)

\(b.4x+3x=30-20:10\)

\(7x=30-2\)

\(7x=28\)

\(x=28:7\)

\(x=4\)

\(c.\left(x-28\right):12=5\)

\(x-28=5\times12\)

\(x-28=60\)

\(x=60+28\)

\(x=88\)

\(d.7x-2x=5^{69}:5^{67}\)

\(5x=5^2\)

\(x=5^2:5\)

\(x=25:5\)

\(x=5\)

\(e.1440:\left[120-\left(3x+9\right)\right]=120\)

\(120-\left(3x+9\right)=1440:120\)

\(120-\left(3x+9\right)=12\)

\(3x+9=120-12\)

\(3x+9=108\)

\(3x=108-9\)

\(3x=99\)

\(x=99:3\)

\(x=33\)

Answer 2

` (x - 3) : 2 = 5^14 : 5^12`

\(\left(x-3\right):2=5^{14-12}\)

\(\left(x-3\right):2=5^2\)

\(\left(x-3\right):2=25\)

\(x-3=25\times2\)

\(x-3=50\)

\(x=50+3\)

`x=53`

___________________________

`4x +3x = 30 - 20 : 10`

`4x + 3x = 30 - 2`

` 4x - 3x = 28`

` x.(4+3) = 28`

` x . 7 = 28`

` x =28 : 7`

` x = 4`

______________________

`( x - 28) : 12 = 5`

`(x - 28) = 5 xx 12`

`x - 28= 60`

` x = 60 + 28`

` x = 88`

_____________________

` 7x - 2x = 5^69 : 5^67`

\(7x-2x=5^{69-67}\)

`7x - 2x = 5^2`

` 7x - 2x = 25`

` x . ( 7 -2) = 25`

` x. 5 = 25`

` x = 25 : 5`

` x = 5`

_________________

` 1440 : [ 120 - (3x + 9)] = 120`

` [ 120 - (3x + 9)] = 1440 : 120`

` [ 120 - (3x + 9)]  = 12`

` ( 3x + 9) = 120 - 12`

` ( 3x + 9) = 108`

` 3x + 9 = 108`

` 3x = 108 - 9`

` 3x = 99`

` x = 99 : 3`

` x = 33`

Answer 3

a) \(\left(x-3\right):2=5^{14}:5^{12}\)

`=> (x-3) : 2 = 5^2 =25`

`=> x-3 = 25.2=50`

`=>x=50+3=53`

b)`4x+3x=30-20:10`

`=>(4+3)x = 30 -2`

`=> 7x =28`

`=> x= 28/7 = 4`

c)`(x-28):12=5`

`=>x-28 = 5.12=60`

`=>x=60+28 = 88`

d)`7x-2x=5^69 : 5^67`

`=>(7-2)x = 5^69-67`

`=>5x= 5^2 =5.5`

`=>x=5`

e)`1440 : [120 - (3x+9)] =120`

`=> 120-(3x +9 )= 1440 :120 = 12`

`=> 3x+9 = 120 -12 =108`

`=> 3x = 108 -9 =99`

`=>x = 99/3 =33`

Answer 4

d)`7x-2x=5^69 : 5^67`

`=>(7-2)x = 5^69-67`

`=>5x= 5^2 =5.5`

`=>x=5`

e)`1440 : [120 - (3x+9)] =120`

`=> 120-(3x +9 )= 1440 :120 = 12`

`=> 3x+9 = 120 -12 =108`

`=> 3x = 108 -9 =99`

`=>x = 99/3 =33`

Answer 5

a) \(\left(x-3\right):2=5^{14}:5^{12}\)

`=> (x-3) : 2 = 5^2 =25`

`=> x-3 = 25.2=50`

`=>x=50+3=53`

b)`4x+3x=30-20:10`

`=>(4+3)x = 30 -2`

`=> 7x =28`

`=> x= 28/7 = 4`

c)`(x-28):12=5`

`=>x-28 = 5.12=60`

`=>x=60+28 = 88`

Answer 6

a\53

b\4

c\88

d\5

e\33

Answer 7

a.(x−3):2=514:512a.(x−3):2=514:512

d.7x−2x=569:567d.7x−2x=569:567