Tìm x

A. -6 phần 12 - x = 9 phần 48

To solve for x, we need to simplify both sides of the equation.

-6 phần 12 can be simplified to -1 phần 2.

9 phần 48 can be simplified to 3 phần 16.

So the equation becomes:

-1 phần 2 - x = 3 phần 16

To get rid of the fraction, we can multiply both sides of the equation by the least common multiple (LCM) of the denominators, which is 16.

16 * (-1 phần 2) = 16 * (3 phần 16)

-8 = 3

This is not a true statement, so there is no solution for x in this equation.

Therefore, option A is not correct.

B. x 4 phần 6 = 5 phần 25 + 7 phần 15

To solve for x, we need to simplify both sides of the equation.

4 phần 6 can be simplified to 2 phần 3.

5 phần 25 can be simplified to 1 phần 5.

7 phần 15 cannot be simplified further.

So the equation becomes:

x 2 phần 3 = 1 phần 5 + 7 phần 15

To add fractions, we need to find a common denominator. The least common multiple (LCM) of 3, 5, and 15 is 15.

x 2 phần 3 = 3 phần 15 + 7 phần 15

x 2 phần 3 = 10 phần 15

To simplify further, we can divide both sides of the equation by 2.

x = 5 phần 15

5 phần 15 can be simplified to 1 phần 3.

So the solution for x is 1 phần 3.

Therefore, option B is correct.

C. x + 5 phần 6 = 16 phần 42 - 8 phần 56

To solve for x, we need to simplify both sides of the equation.

5 phần 6 can be simplified to 5 phần 3.

16 phần 42 can be simplified to 8 phần 21.

8 phần 56 can be simplified to 1 phần 7.

So the equation becomes:

x + 5 phần 3 = 8 phần 21 - 1 phần 7

To subtract fractions, we need to find a common denominator. The least common multiple (LCM) of 3 and 7 is 21.

x + 5 phần 3 = 8 phần 21 - 3 phần 21

x + 5 phần 3 = 5 phần 21

To simplify further, we can subtract 5 phần 3 from both sides of the equation.

x = 5 phần 21 - 5 phần 3

x = 5 phần 21 - 35 phần 21

x = -30 phần 21

-30 phần 21 can be simplified to -10 phần 7.

So the solution for x is -10 phần 7.

Therefore, option C is correct.

D. x + 4 phần 5 = 6 phần 20 - (-7) phần 3

To solve for x, we need to simplify both sides of the equation.

4 phần 5 can be simplified to 4 phần 5.

6 phần 20 can be simplified to 3 phần 10.

-(-7) phần 3 can be simplified to 7 phần 3.

So the equation becomes:

x + 4 phần 5 = 3 phần 10 + 7 phần 3

To add fractions, we need to find a common denominator. The least common multiple (LCM) of 5 and 10 is 10.

x + 4 phần 5 = 3 phần 10 + 14 phần 10

x + 4 phần 5 = 17 phần 10

To simplify further, we can subtract 4 phần 5 from both sides of the equation.

x = 17 phần 10 - 4 phần 5

x = 17 phần 10 - 8 phần 10

x = 9 phần 10

9 phần 10 can be simplified to 9 phần 10.

So the solution for x is 9 phần 10.

Therefore, option D is correct.

E. x + 7 phần 8 = 13 phần 12

To solve for x, we need to simplify both sides of the equation.

7 phần 8 can be simplified to 7 phần 8.

13 phần 12 can be simplified to 13 phần 12.

So the equation becomes:

x + 7 phần 8 = 13 phần 12

To subtract fractions, we need to find a common denominator. The least common multiple (LCM) of 8 and 12 is 24.

x + 7 phần 8 = 13 phần 24

To simplify further, we can multiply both sides of the equation by 24.

24(x + 7 phần 8) = 24(13 phần 24)

24x + 24(7 phần 8) = 13

24x + 21 = 13

To isolate x, we can subtract 21 from both sides of the equation.

24x = 13 - 21

24x = -8

To solve for x, we can divide both sides of the equation by 24.

x = -8/24

x = -1/3

So the solution for x is -1/3.

Therefore, option E is correct.