WILL MARK BRAINLIEST <br> What is the value of j?

I don’t get what it means by “Identify the graphs of proportional relationships.”

Ymorist [56]

C and B is proportional relationships , because the proportional relationships always start at zero and the line must be straight !

5 0

3 years ago

DIscrete Math

Daniel [21]

Answer:

Step-by-step explanation:

As the statement is ‘‘if and only if’’ we need to prove two implications

$f : X \rightarrow Y$ is surjective implies there exists a function $h : Y \rightarrow X$ such that $f\circ h = 1_Y$ .
If there exists a function $h : Y \rightarrow X$ such that $f\circ h = 1_Y$ , then $f : X \rightarrow Y$ is surjective

Let us start by the first implication.

Our hypothesis is that the function $f : X \rightarrow Y$ is surjective. From this we know that for every $y\in Y$ there exist, at least, one $x\in X$ such that $y=f(x)$ .

Now, define the sets $X_y = \{x\in X: y=f(x)\}$ . Notice that the set $X_y$ is the pre-image of the element $y$ . Also, from the fact that $f$ is a function we deduce that $X_{y_1}\cap X_{y_2}=\emptyset$ , and because $f$ the sets $X_y$ are no empty.

From each set $X_y$ choose only one element $x_y$ , and notice that $f(x_y)=y$ .

So, we can define the function $h:Y\rightarrow X$ as $h(y)=x_y$ . It is no difficult to conclude that $f\circ h(y) = f(x_y)=y$ . With this we have that $f\circ h=1_Y$ , and the prove is complete.

Now, let us prove the second implication.

We have that there exists a function $h:Y\rightarrow X$ such that $f\circ h=1_Y$ .

Take an element $y\in Y$ , then $f\circ h(y)=y$ . Now, write $x=h(y)$ and notice that $x\in X$ . Also, with this we have that $f(x)=y$ .

So, for every element $y\in Y$ we have found that an element $x\in X$ (recall that $x=h(y)$ ) such that $y=f(x)$ , which is equivalent to the fact that $f$ is surjective. Therefore, the prove is complete.

3 0

3 years ago

Dr. Goodrich wanted to demonstrate that his tires were better than those of his competitor, Dr. Goodyear. From car registration

dem82 [27]

Answer:

Dependent Variable : Tire tread wear ; Independent Variable : Tire Brand ; Confounding Variable : Person driving

Step-by-step explanation:

Dependent Variable is the variable being affected by independent variable(s). Independent Variable(s) are the causal variable, bring change in dependent variable.

Goodrich wants to demonstrate that his tires were better than those of his competitor (Goodyear). For that, he has got conducted an independent research on tires worn quality - brand wise & various factors affecting wear

Dependent Variable is the 'Tire tread wear '.
Independent Variables determining it is primarily brand : Goodrich / Goodyear ; secondarily - price, mileage, time etc

Confounding variable is an extraneous influence variable; that changes the relationship between independent & dependent variable, outcome of experimental research.

In this case : Individuals driving the vehicles could be a confounding variable. A particular person could wear out tire more than another person.

6 0

3 years ago

Use the reverse tabular method to solve division problem: (x^3+2x^2+2x+1)/(x+1)

belka [17]

Answer:

x^2+x+1

Step-by-step explanation:

Your welcomeeee

7 0

3 years ago

Find equation of set of points pieces that its distance from the point 3, 4, -5 and -2, 1, 4 are equal.