Since he started with Nothing
He had zero initially
After x Months...
He'll have 10x naxvips
in slope intercept form
y=10x
To get the y values ... substitute the corresponding x value
For x=0
y=10(0)
y=0. Which is true cos he had no naxvip initially
x=1
y=10(1)
=10. Which is true cos he buys 10 more monthly... So 10 + 0 = 10.
x=2
y=10(2) = 20. This is true cos he added an additional 10 after each month
x=7
y=70.
