The table below shows the amount that must be repaid, y, when x dollars are borrowed.
1 answer:
Answer:
see below
Step-by-step explanation:
You can try the answer choices to see which one works. Since the amount repaid is greater than the amount borrowed, you can be pretty sure that the multiplier of x will not be 4/5 (a value less than 1).
You can see right away that
y = 5/4x
does not work for x=100, because it gives y=(5/4)(100) = 125, and the table value is 135. Note that 135 is 10 more than 125, so we expect that ...
y = 5/4x +10
will be correct. Trying that function on the other table values shows it fits exactly:
5/4(200) +10 = 250 +10 = 260
5/4(500) +10 = 625 +10 = 635
5/4(800) +10 = 1000 +10 = 1010
_____
You can also use the table values to create the relation equation. One possible method uses the 2-point form of the equation for a line:
y = (y2 -y1)/(x2 -x1)(x -x1) +y1
y = (260 -135)/(200 -100)(x -100) +135
y = 125/100(x -100) +135 . . . . simplify a bit
y = 5/4x -125 +135 . . . . . . . . . simplify more
y = 5/4x +10 . . . . . . . . . . . . . . simpler yet; matches 3rd choice
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