Zachary purchased a computer for $1,400 on a payment plan. Two months after he purchased the computer, his valence was $1,120. Three months after he purchased the computer, his balance was $980. What is an equation that models the balance y after x months??

9514 1404 393

  y = 1400 -140x

Step-by-step explanation:

In the first two months, Zachary paid ...

  1400 -1120 = 280

so 280/2 = 140 per month. This is the amount that the balance decreases each month from the starting balance of $1400.

Zachary's balance (y) can be modeled as ...

  y = 1400 -140x

more detail

step-by-step explanation:

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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