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3 years ago

1. Solve the system by substitution- 2x+y=-11, 3x-4y=11.

Mathematics

2 answers:

andre [41]3 years ago

8 0

Thank you so much broskie

Maksim231197 [3]3 years ago

4 0

In the first equation, moving 2x over gives "y = -2x-11". Placing this into the second equation gives "3x - 4(-2x-11) = 11", or "3x+8x+44 = 11", which can be reduced to "11x= -33" or "x = -3". Replacing the "x" with -3 in the first equation gives "-6 + y = -11" or "y = -5". This gives a solution of (-3, -5), or answer C.

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Find the local extreme values of the function f(x, y) = xy - x2 - y2 - 3x - 3y + 12

aev [14]

$f(x,y)=xy-x^2-y^2-3x-3y+12$

First compute the first-order partial derivatives and find the critical points.

$f_x=y-2x-3$
$f_y=x-2y-3$

Both first order derivatives vanish at $(x,y)=(-3,-3)$ .

Computing the Hessian, we get

$\mathbf H(x,y)=\begin{bmatrix}f_{xx}&f_{xy}\\f_{yx}&f_{yy}\end{bmatrix}=\begin{bmatrix}-2&1\\1&-2\end{bmatrix}$

We have $\det\mathbf H(x,y)=3>0$ , which means $(-3,-3)$ is an extremum of $f(x,y)$ . Since $f_{xx}(-3,-3)=-2$ , this extremum is a local maximum of $f(x,y)$ with a value of 21.

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3 years ago

What is the y-intercept of the graph of y = 3x^2 – 6x – 8? –8 –6 1 3

Shkiper50 [21]

y-intercept: set x=0 

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y = -8 

x-intercept: set y=0 

0 = 3x^2 - 6x - 8

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3 years ago

Find x. See attached picture.

pishuonlain [190]

Answer:

B. 22

Step-by-step explanation:

We know tan60=

$\sqrt{3}$

Let common side be x

Tan = opp/adj= sqrt(3)

$\frac{11 \sqrt{6} }{x} = \sqrt{3}$

Transposing we get :

$\frac{11 \sqrt{6} }{ \sqrt{3}} = x = 11 \sqrt{2}$

Now, we know that since the other triangle is a 45-45-90 triangle, we can state that the side adjacent to the given angle = 11 sqrt(2) as the two sides are equal due to the triangle being an isoceles triangle.

Solve for x by using Pythagorean theorem:

$\sqrt((11 \sqrt{2}^{2} + (11 \sqrt{2} )^{2} ) = x$

$= > \sqrt{2(11 \times 11 \times \sqrt{2} \times \sqrt{2}) } = x$

$= > \sqrt{484} = x = 22$

Hence answer is B. 22

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1 year ago

Rachel jogged along a trail that was 1/4 of a mile long. She logged along the trail 8 times. How many miles did Rachel job

kow [346]

2 miles should be the answer because 1/4x8=2

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2 years ago

- 3x + y = 3 2y = -3x - 12

Lynna [10]

Answer:

x=-2, y=-3

Step-by-step explanation:

we can rearrange the questions to make it easier

y=3x+3

2y=-3x-12

if you add the two equations, you get

3y=0x-9

so y=-9/3 = -3

plug y into one of the equations

-3=3x+3

-6=3x

x=-2

and then check your work by plugging into the other equation:

2*-3=-3(-2)-12

-6=6-12

-6=-6

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2 years ago