The video describes how to find 'x' in the algebraic equation
-3x + 7x - 6 = 30
The equation is solved on a white board by hand.
The method shown uses the following steps:
Firstly both 'x' terms are added together to get the equation 4x - 6 = 30.
Then 6 is added to both sides to get 4x = 36.
Now we divide both sides by 4, to get x = 9.
Once the equation is solved, the video then goes over how to check that your solution is correct, by substituting 9 in for 'x' and making sure both sides have the same value.