You borrow $90 from Grandma. You pay back $15 a week. Write an equation in standard form that represents the amount owed(y) after x weeks.

90 - 15x = y

y=15x-90

To write an equation that represents the amount owed after a certain number of weeks, let's break down the information given.

Initially, you borrowed $90 from Grandma. Each week, you pay back $15. This means that the amount owed decreases by $15 each week.

Let's assign variables to the given information:
- Let x represent the number of weeks.
- Let y represent the amount owed.

The amount owed after x weeks can then be determined by subtracting the total payments ($15 per week) from the original amount borrowed ($90).

The equation can be written as:
y = 90 - 15x

To put this equation in standard form, we arrange it with the variables on the left side and the constants on the right side. So, let's rearrange it:
15x + y = 90

Therefore, the equation in standard form that represents the amount owed (y) after x weeks is 15x + y = 90.