Question

Bài 2. (1 điểm) Tìm $x,$ biết:

a) $2( 3x-1) = 10 $;

b) $\left( 3x+4 \right)^2-\left( 3x-1 \right)\left( 3x+1 \right)=49$.

Answer 1

a) 2(3x - 1) = 10

3x - 1 = 10 : 2

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32 : 24

x = 4/3

Answer 2

a) \(2\left(3x-1\right)=10\)

\(3x-1=5\)

\(3x=6\)

\(x=2\)

b) \(\left(3x+4\right)^2-\left(3x-1\right)\left(3x+1\right)=49\)

\(9x^2+24x+16-9x^2+1=49\)

\(24x=49-1-16=32\)

\(x=\dfrac{32}{24}=\dfrac{4}{3}\)

Answer 3

b

Answer 4

a) 2(3x - 1) = 10

3x - 1 = 10 : 2

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32 : 24

x = 4/3

Answer 5

2.

a) Ta có: 2(3x-1) = 10

6x - 2 = 10

6x = 10+2

6x = 12

x = 12:6

x = 2

Vậy: x = 2

b, (3x+4)² - (3x-1)(3x+1) = 49

9x² + 24x + 16 - (9x² - 1²) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x = 49 - 16 - 1

24x = 32

x = 32 : 24

x = 4/3

Vậy: x = 4/3

Answer 6

 

a) 2(3x - 1) = 10

3x - 1 = 10 : 2

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32 : 24

x = 4/3

Answer 7

a) 2(3x−1)=10

    6x - 2        = 10

       x            = \(\dfrac{4}{3}\)

b) (3x+4)2−(3x−1)(3x+1)=49

    9x² + 24x + 16 - 9x² + 1         = 49

                                24x + 17      =49

                                    x               =\(\dfrac{4}{3}\)

Answer 8

a) 2 | b) 17 phần 12

Answer 9

Hw

Answer 10

a) $2(3x-1)=10$

$6x-2=10$

$6x=12$

$x=2$

Vậy $x=2$

b) $(3x+4)^2-\left(3x-1\right)\left(3x+1\right)=49$

$9x^2\; +24x+16-9x^2\; +1=49$

$24x=32$

x=43x= 4/3

​

Vậy x=43x=

​.4/3

Answer 11

a)2(3x-1)=10
6x-2=10

6x=12

x=2

Vậy x=2

b)(3x+4)^2-(3x-1)(3x+1)=49

9x^2+24x+16-9x^2-1=49

24x+15=49

24x=34

X=17/12

Vậy x=17/12

Answer 12

a) 2( 3x - 1) = 10

6x - 2 = 10 

6x     =10+2

6x    = 12

x       =12: 6

x       = 2

vậy x= 2

b)

6,6

Answer 13

a) 2( 3x - 1) = 10

6x - 2 = 10 

6x     =10+2

6x    = 12

x       =12: 6

x       = 2

vậy x= 2

b)

6,6

Answer 14

a) 2( 3x - 1) = 10

6x - 2 = 10 

6x     =10+2

6x    = 12

x       =12: 6

x       = 2

vậy x= 2

b)

6,6

Answer 15

a)2(3x-1)=10

6x-2=10

6x=10+2

x=12÷6

x=2

b)(3x+4)²−(3x−1)(3x+1)=49

​9x²+24+16-9x²+1=49

24x=32

x=4/3

​

 

Answer 16

a,2 (3x-1) =10

   6x-2 =10

    6x   =12

      x   =2

vậy x=2

b,(3x+4)²-(3x-1) (3x+1) =49

  9x²+24x+16-9x²+1=49

        24x+17=49

        24x      =32

             x      =4/3

vậy x = 4/3

Answer 17

a) 2(3x - 1) = 10 

    6x - 2 = 10

    6x      = 10 + 2

    6x      = 12

    x        = 12 : 6

    x        = 2

Vậy x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

    9x² + 24x + 16 - 9x² + 1 = 49

    24x + 17 = 49

    24x         = 49 - 17

    24x         = 32

     x            = 32 : 24

     x            = \(\dfrac{4}{3}\)

Vậy x = \(\dfrac{4}{3}\)

Answer 18

a) $2(3x-1)=10$

$6x-2=10$

$6x=12$

$x=2$

Vậy $x=2$

b) (3x+4)2−(3x−1)(3x+1)=49(3x+4)2−(3x−1)(3x+1)=49

9x2+24x+16−9x2+1=499x2+24x+16−9x2+1=49

$24x=32$

x=43x=34​

Vậy x=43x=34​.​

Answer 19

a) 2(3x - 1) = 10

3x - 1 = 10 : 2

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32 : 24

x = 4/3

Answer 20

a) x=2

b)x=4/3

Answer 21

a) 2(3x - 1) = 10

6x - 2 = 10

6x = 10 : 2

x = 5 : 6

x = 5/6

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - (9x² + 3x - 3x + 1) = 49

9x² + 24x + 16 - 9x² - 3x + 3x -1 = 49

9x² + 24x - 9x² - 3x + 3x = 49 + 1 - 16

24x = 34

x = 34 : 24

x = 34/24

 

Answer 22

a) 2(3x - 1) = 10

3x - 1 = 10 : 2

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

b) (3x + 4)² - (3x - 1)(3x + 1) = 49

9x² + 24x + 16 - 9x² + 1 = 49

24x + 17 = 49

24x = 49 - 17

24x = 32

x = 32 : 24

x = 4/3

Answer 23

a)

3x-1=10:2

3x-1=5

3x=5+1

3x=6

x=2

b)

9x²+24x+16-(9x²-1)=49

9x²+24x+16-9x²+1=49

24x+17=49

24x=49-17

24x=32

x=4/3

Answer 24

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