7x - 4 and 5x + 4 are the lengths of two of the sides of a rhombus. What is the value of x? If there is not enough information to find x, enter 999.​

All the sides of a rhombus are equal and opposite sides parallel and equal.

Therefore by understanding the above we can deduce that:

7x - 4 = 5x + 4

7x - 4 + 4 - 5x = 5x + 4 + 4 - 5x (Separate all the terms with x to go to the other side of the equals sign and do the some for the constants).

7x - 5x + (4 - 4) = (5x - 5x) + 4 + 4

7x - 5x = 4 + 4

2x = 8

2x/2 = 8/2

x = 4

x = 4

Step-by-step explanation:

7x - 4 = 5x + 4

7x-4-5x = 5x+4-5x

2x-4 = 4

2x-4+4 = 4 + 4

2x = 8

2x / 2 =  8/ 2

x = 4

its definatley   this on your answer choice?