Three texas drovers met on a highway and began to dicker as follows:
hank says to jim: "i'll give you six pigs for a horse; then you'll have twice as many critters in your drove as i will have in mine."
duke says to hank: i'll give you fourteen sheep for a horse; then you'll have three times as many critters as i." jim says to duke: i'll give you four cows for a horse; then you'll have six times as many critters as i."
from these interesting facts, can you tell how many animals were in each
of the three droves?

Step-by-step explanation:

Let J, D, and H represent the drove sizes of Jim, Duke, and Hank.

  2(H -6 + 1) = (J +6 -1) . . . . . Hank's offer

  3(D -14 +1) = (H +14 -1) . . . . Duke's offer

  6(J -4 +1) = (D +4 -1) . . . . . . Jim's offer

These equations can be simplified to ...

  2H - J = 15

  3D - H = 52

  6J - D = 21

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Solution

Adding twice the second equation to the first gives ...

  2(3D -H) +(2H -J) = 2(52) +(15)

  6D -J = 119

Adding 6 times the third equation to this one gives ...

  6(6J -D) +(6D -J) = 6(21) +(119)

  35J = 245

  J = 7

Using this value in the third equation gives ...

  6(7) -D = 21

  42 -21 = D = 21

Using the value of J in the first equation gives ...

  2H -7 = 15

  H = (15 +7)/2 = 11

Then the solution is (J, D, H) = (7, 21, 11).

Jim's drove had 7 animals; Duke's drove had 21 animals; Hank's drove had 11 animals.

when functions are first introduced, you will probably have some simplistic "functions" and relations to deal with, usually being just sets of points. these won't be terribly useful or interesting functions and relations, but your text wants you to get the idea of what the domain and range of a function are. small sets of points are generally the simplest sorts of relations, so your book starts with those.

step-by-step explanation:

state the domain and range of the following relation. is the relation a function?

{(2, –3), (4, 6), (3, –1), (6, 6), (2, 3)}

the above list of points, being a relationship between certain x's and certain y's, is a relation. the domain is all the x-values, and the range is all the y-values. to give the domain and the range, i just list the values without duplication:

domain: {2, 3, 4, 6}

range: {–3, –1, 3, 6}

(it is customary to list these values in numerical order, but it is not required. sets are called "unordered lists", so you can list the numbers in any order you feel like. just don't duplicate: technically, repetitions are okay in sets, but most instructors would count off for this.)

while the given set does indeed represent a relation (because x's and y's are being related to each other), the set they gave me contains two points with the same x-value: (2, –3) and (2, 3). since x = 2 gives me two possible destinations (that is, two possible y-values), then this relation is not a function.

note that all i had to do to check whether the relation was a function was to look for duplicate x-values. if you find any duplicate x-values, then the different y-values mean that you do not have a function. remember: for a relation to be a function, each x-value has to go to one, and only one, y-value.

state the domain and range of the following relation. is the relation a function?

{(–3, 5), (–2, 5), (–1, 5), (0, 5), (1, 5), (2, 5)}

i'll just list the x-values for the domain and the y-values for the range: