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3 years ago

Please help, last week of school and I don’t understand this at all

Mathematics

2 answers:

hoa [83]3 years ago

4 0

Answer:

The correct answer is B

Step-by-step explanation:

It's because when you're graphing the equation, more than or equal to symbol is a black line, therefore you can cross out A and C. It's B because it's more than 0, D if it was graphed would have the other side shaded, therefore its b

rodikova [14]3 years ago

3 0

Answer:

The answer to the problem is C

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Tell whether this statement is sometimes, always, or never true. Identify the answer with a sketch. If B is a point between A an

Ksivusya [100]

The statement is always true

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3 years ago

There are 8 tennis players in a round robin tournament, which means each team will play every other team once. How many matches

Aliun [14]

<h3>Answer: 28</h3>

==========================================================

Explanation:

Method 1

Imagine a table with 8 rows and 8 columns to represent all possible match-ups. You can actually draw out this table or just think of it as a thought experiment.

There are 8*8 = 64 entries in the table. Along the northwest diagonal, we have each team pair up with itself. This is of course silly and impossible. We cross off this entire diagonal so we drop to 64-8 = 56 entries.

Then notice that the lower left corner is a mirror copy of the upper right corner. A match-up like AB is the same as BA. So we must divide by 2 to get 56/2 = 28 different matches.

----------------------------------

Method 2

There are 8 selections for the first slot, and 8-1 = 7 selections for the second slot. We have 8*7 = 56 permutations and 56/2 = 28 combinations.

----------------------------------

Method 3

Use the nCr combination formula with n = 8 and r = 2

$n C r = \frac{n!}{r!(n-r)!}\\\\8 C 2 = \frac{8!}{2!*(8-2)!}\\\\8 C 2 = \frac{8!}{2!*6!}\\\\8 C 2 = \frac{8*7*6!}{2!*6!}\\\\ 8 C 2 = \frac{8*7}{2!}\\\\ 8 C 2 = \frac{8*7}{2*1}\\\\ 8 C 2 = \frac{56}{2}\\\\ 8 C 2 = 28\\\\$

There are 28 combinations possible. Order doesn't matter (eg: match-up AB is the same as match-up BA).

Notice how the (8*7)/2 expression is part of the steps shown above in the nCr formula.

7 0

1 year ago

A<br> Write the equation for<br> line that<br> passes through (1, 1) and (-1,7)

KengaRu [80]

Answer:y=-3x+4

Step-by-step explanation:

You want to find the equation for a line that passes through the two points:

(1,1) and (-1,7).

First of all, remember what the equation of a line is:

y = mx+b

Where:

m is the slope, and

b is the y-intercept

First, let's find what m is, the slope of the line...

The slope of a line is a measure of how fast the line "goes up" or "goes down". A large slope means the line goes up or down really fast (a very steep line). Small slopes means the line isn't very steep. A slope of zero means the line has no steepness at all; it is perfectly horizontal.

For lines like these, the slope is always defined as "the change in y over the change in x" or, in equation form:

So what we need now are the two points you gave that the line passes through. Let's call the first point you gave, (1,1), point #1, so the x and y numbers given will be called x1 and y1. Or, x1=1 and y1=1.

Also, let's call the second point you gave, (-1,7), point #2, so the x and y numbers here will be called x2 and y2. Or, x2=-1 and y2=7.

Now, just plug the numbers into the formula for m above, like this:

7 - 1

-1 - 1

or...

-2

or...

m=-3

So, we have the first piece to finding the equation of this line, and we can fill it into y=mx+b like this:

y=-3x+b

Now, what about b, the y-intercept?

To find b, think about what your (x,y) points mean:

(1,1). When x of the line is 1, y of the line must be 1.

(-1,7). When x of the line is -1, y of the line must be 7.

Because you said the line passes through each one of these two points, right?

Now, look at our line's equation so far: y=-3x+b. b is what we want, the -3 is already set and x and y are just two "free variables" sitting there. We can plug anything we want in for x and y here, but we want the equation for the line that specfically passes through the two points (1,1) and (-1,7).

So, why not plug in for x and y from one of our (x,y) points that we know the line passes through? This will allow us to solve for b for the particular line that passes through the two points you gave!.

You can use either (x,y) point you want..the answer will be the same:

(1,1). y=mx+b or 1=-3 × 1+b, or solving for b: b=1-(-3)(1). b=4.

(-1,7). y=mx+b or 7=-3 × -1+b, or solving for b: b=7-(-3)(-1). b=4.

See! In both cases we got the same value for b. And this completes our problem.

The equation of the line that passes through the points

(1,1) and (-1,7)

y=-3x+4

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3 years ago

What is -5g + 15h - 25

lukranit [14]

Answer:

15h

Step-by-step explanation

-5g plus 15h is 10 h minus 25 is 15h

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3 years ago

What is the greatest possible error for a measurement of 25 gallons

goldenfox [79]

the greatest possible error is 0.5

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3 years ago