Let p be the prize of a pen and m the prize of a mechanical pencils. If you buy six pens and one mechanical pencil, you spend 6p+m. We know that this equals 9, because you get 1$ change from a 10$ bill.
Similarly, if you buy four pens and two mechanical pencils, you spend 4p+2m, which is 8$, because now you get a $2 change. Put these equation together in a system:

Now, if you multiply the first equation by 2, the system becomes

Subtract the second equation from the first:

Plug this value into the first equation to get

there is an equation for straight lines which goes
y-y,=m(x-x,)
where( x, , y, ) is any coordinate on the line and m is the gradient
so your answer is
y-7= -2(x-4)
does this make sense?
Ok, so for this you're likely graphing in y=mx+b format (slope intercept). So to start, you'all first subtract 3x from the equation to get 6y=-3x+16. Now you'll divide the equation by 6 to get y alone. Your final equation will be y=-1/2x+16/6
Let the value of the vehicle be described by the equation
V = a + bx
where x = number of years since purchase
a,b are constants.
When x = 0, V = $7500. Therefore
a + b*0 = 7500
a = 7500
When x = 7, V = $500. Therefore
7500 + 7b = 500
7b = 500 -7500 = -7000
b = -7000/7 = -1000
The equation is
V = 7500 - 1000x
The slope of this equation is the depreciation rate, and it is -$1000 per year.
Answer: $1000 depreciation per year.
Answer:
5
Step-by-step explanation:
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