Question

You borrowed 90 dollars from your grandmother. You pay back 15 dollars each week. Write in standard form an equation in which y is the amount of money owed after x weeks.

Answer 1

y= money borrowed minus money paid times number of weeks

x = weeks
Ans: y = $90 - $15x

Answer 2

y = -15x + 90

But that's not in standard form (it's in slope-intercept form). So, to change the equation into standard form, add 15x to each side.

y = -15x + 90
y + 15x = -15x + 90 + 15x
15x + y = 90

Hope this helped :)