Determine the slope of the points (-2, -7) and (0, -1)

First let's find the slope of the line through the points  and  

Note:  is the first point . So this means that x%5B1%5D=-2 and y%5B1%5D=0.

Also,  is the second point . So this means that x%5B2%5D=0 and y%5B2%5D=3.

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.

m=%283-0%29%2F%280--2%29 Plug in y%5B2%5D=3, y%5B1%5D=0, x%5B2%5D=0, and x%5B1%5D=-2

m=%283%29%2F%280--2%29 Subtract 0 from 3 to get 3

m=%283%29%2F%282%29 Subtract -2 from 0 to get 2

So the slope of the line that goes through the points  and  is m=3%2F2

Now let's use the point slope formula:

y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula

y-0=%283%2F2%29%28x--2%29 Plug in m=3%2F2, x%5B1%5D=-2, and y%5B1%5D=0

y-0=%283%2F2%29%28x%2B2%29 Rewrite x--2 as x%2B2

y-0=%283%2F2%29x%2B%283%2F2%29%282%29 Distribute

y-0=%283%2F2%29x%2B3 Multiply

y=%283%2F2%29x%2B3 Simplify

So the equation that goes through the points  and  is y=%283%2F2%29x%2B3

Notice how the graph of y=%283%2F2%29x%2B3 goes through the points  and . So this visually verifies our answer.

Graph of y=%283%2F2%29x%2B3 through the points  and

Step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18

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: