Question

Tìm số tự nhiên \(x\), biết :

a) \(219-7\left(x+1\right)=100\)

b) \(\left(3x-6\right).3=3^4\)

Answer 1

a) 219 - 7(x + 1) = 100 <=> 7(x+1) = 219 - 100
<=> 7(x+1) = 119 <=> x + 1 = 119 : 7 <=> x + 1 = 17

<=> x = 17 - 1 <=> x = 16
b) (3x - 6).3 = 3434 <=> 3x - 6 = 3434 : 3 <=> 3x - 6 = 3333
<=> 3x = 27 + 6 <=> 3x = 33 <=> x = 11

Answer 2

a)

- 7(x+ 1)= - 119

x+1 = -119 : (-7)

x+1 = 17

x= 17-1

x= 16

b) (3x - 6). 3 = 3⁴

(3x - 6). 3 = 81

(3x - 6)= 81: 3

(3x - 6)= 27

3x= 27+ 6

3x= 33

x= 33:3

x= 11

b)

Answer 3

a) 219 - 7( x + 1 ) = 100

7( x + 1 ) = 219 - 100

7( x + 1 ) = 119

x + 1 = 219 : 7

x + 1 = 17

x = 17 - 1

x = 16

b) ( 3x - 6 ) . 3 = 3⁴

( 3x - 6 ) . 3 = 81

3x - 6 = 81 : 3

3x - 6 = 27

3x = 27 + 6

3x = 33

x = 33 : 3

x = 11

Answer 4

219 - 7 .( x + 1 ) =100 (3x - 6 ) . 3 = 3⁴

7 . (x+1)=219-100 (3x - 6 ) .3 = 81

7.(x+1)=11 (3x - 6 ) =81 :3

x+1 = 119: 7 (3x -6 ) =27

x+1=17 3x = 27+6

x= 17-1 3x =33

x=16 x =33 :3

x =11

Đó là cách làm

CHÚC BẠN MĂY MẮN

Answer 5

a) 219 - 7 ( x +1)= 100

7 ( x +1)= 219 +100

7 ( x +1)= 390

x +1= 390 : 7

x +1 = \(\frac{390}{7}\)

x = \(\frac{390}{7}\) -1

x = \(\frac{383}{7}\) b) (3x - 6) . 3= 3⁴ (3x - 6) . 3 = 81 (3x - 6) = 81 : 3 3x - 6 = 27 3x = 27+ 6 3x = 33 x =33 : 3 x = 11