Answer:
The correct answer is x+300=-50
Explanation:
Let's analyze the information we have: 
We know that Jason's account balance left -50 as a result. 
We know he had $ 300 before. 
What we do not know is what is the value you had to pay for your bills, so we will assign an x. 
The bills + the money that he already had (300) resulted in -50 
So: 
X + 300 = -50 
X = -50-300 
X = -350 
The total bills Jason had to pay was $ 350