Hey there!!
Given equation :
... 6 - 4x = 7x - 9x - 4
Combining like terms :
... 6 - 4x = - 2x - 4
Adding 4x on both sides :
... 6 = 2x - 4
Adding 4 on both sides :
... 2x = 10
Dividing by 2 on both sides :
... x = 5
Hence, the value of x is 5.
Hope my answer helps!!