N=410,439
You can just type your problem into a calculator-- you're just finding out what 420,008-9,569 is. :)
So slope intercept form is y=mx+b
m=slope b=y intercept
convert current equation to slpe intercept
y-4=x-8
add 4 to both sides
y=x-4
tada
Number of nickels plus number of dimes equals total number of coins
so
n + d = 40
then they tell us that "there are seven times as many dimes as there are nickels"
this translates to
d = 7n
we then plug that into our first equation
and get
n + 7n = 40
then we solve for n
add like terms
8n = 40
then divide both sides by 8
n = 40/8 = 5
therefore Jimmy has 5 nickels
