Answer:
8,000 points.
Explanation:
Let x be the number of points Melodie have on Khan Academy last week.
We have been given that Melodie has increased her points by 75% in a week. She's at 14,000 points now.
We need to figure out x such that x plus 75% of x equals 14,000. We can represent this information in an equation as:



Upon dividing both sides of our equation by 1.75 we will get,


Therefore, Melodie have 8,000 points on Khan Academy last week.