The new values of x are calculated by the formula
xB - theta * yB. The value of x for the entering variable is set to theta.
In words, you take the old value of x and subtract the quantity theta times yB. Recall, yB was calculated in step 6. Do not forget to set the value of the entering variable to theta. Setting the value of the entering variable to theta makes sense because theta is a measure of how much you can increase the entering variable before driving one of the other basic variables to zero.
Only one more step.