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garri49 [273]
3 years ago
7

5x-y=-15 x+y=-3 USE SUBSTITUTION METHOD

Mathematics
2 answers:
Kobotan [32]3 years ago
7 0

Answer:

5x - y = -15

x + y = -3   ===>  y = -3 -x


5x - (-3 - x) = -15

5x + 3 - x = -15

5x - x = -15 -3

4x = -18

x = -18/4

x = -4.5


x + y = -3

-4.5 + y = -3

y = -3 + 4.5

y = 1.5




Rzqust [24]3 years ago
5 0

What I got was x= -3 and y=0

5x-y=-15

x+y=-3

y=-3-x

5x-(-3-x)=-15 (solve for X)

x=-3

y=-3-(-3)

y=0

(-3,0)

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Calc Q: let f be the fxn that is defined for all real numbers x and that has the follwing properties... f''(x) =24x-18, f'(-1) =
mart [117]
Because we will have to do it eventually, let's find f(x) first.

f''(x) = 24x - 18

First, we integrate f''(x) using an indefinite integral.

f'(x) = ∫ (24x - 18) dx

f'(x) = 12X^2 - 18x + C

Now, we need to find C by substituting "x" for -1 and setting the equation equal to -6 because f'(-1) = -6

f'(-1) = 12(-1)^2 - 18(-1) + C = -6

Solve for C

C=-26

Now we put that into f'(x).

f'(x) = 12x^2 - 18x -26

Now, we integrate again.

f(x) = ∫(12x^2 - 18x - 26)dx

f(x) = 4x^3 - 9x^2 - 26x + C

Now, we substitute "x" for 2 and set it equal to 0.

f(2) = 4(2)^3 - 9(2)^2 - 26(2) + C = 0

Solve for C

C=38

Now that we have f(x), B has been solved.

Next, we need to find out where the slope of f(x) is equal to 0.  Remember that to find slope, we need to find the derivative.  We already found the derivative of f(x), so we can use that.  The question asks for the places where the slope of f(x) is 0, so we need to set f'(x) equal to 0 and solve for "x"

12x^2 - 18x -26 = 0

I could try to factor this, but I know that it is not possible.  We must use the quadratic formula.  I cannot reasonable put the quadratic formula into this, so I will only do the part under the radical.

√[18^2-4(12)(-26)]

√(324+1248)

√1572

√(4)*√(393)

2√393

When this is done with the rest of the formula, you get.

[18+/-2√(393)]/24

Thus, the points where the slope of f(x) is equal to zero are where <span>[18+/-2√(393)]/24 are the x values of f(x).

(  </span>[18+/-2√(393)]/24 , f ( <span>[18+/-2√(393)]/24 )  )

Now, we have done A and B.

To do C, we must remember the formula for finding the average value of f(x)

This formula is:

[The </span>definite integral of f(x)] / (b-a)

The picture is of this formula.

When we solve for this, we get -13.

I hope I got everything right.
4 0
4 years ago
1000p for an answer please
Gwar [14]
Well, it asks that you evaluate 24 for y.
Also, notice that it says "the difference of a number and 6"
So your equation should have been
y - 6

And after evaluating
24 - 6 

Then solve 
24 - 6 = 18
18 should have been the answer

So no, the student's work is not correct, because the student wrote a division expression instead of a subtraction equation
3 0
3 years ago
For his daughter quinceanera Gerardo is considered using one of the two venues a hotel in a city will cost $16,000 for a reserva
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Answer:

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Step-by-step explanation:

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75,000 + 16,000 = 91,000                     90,000 + 1,000 = 91,000

91,000                                                     91,000

I hope this helped :)

7 0
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I just want to make sure that this is correct:
JulsSmile [24]

Answer:

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Step-by-step explanation:

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Evaluate :
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The first one is 43/72 which can’t be simplified

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