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3 years ago

2x(z+4)+1-z+xy; x=4, y=2, z=-3

Mathematics

2 answers:

Marina CMI [18]3 years ago

6 0

Answer:

=20

Step-by-step explanation:

in pic

(hope this helps can I pls have brainlist (crown) ☺️)

Arte-miy333 [17]3 years ago

5 0

$\huge\text{Hey there!}$

<h2> $\large\textsf{2x(z + 4) + 1 - z + xy}$ </h2><h2> $\large\text{= 2(4)(-3 + 4) + 1 - (-3) + 4(2)}$ </h2><h2> $\large\text{= 8(1) + 1 - (-3) + 4(2)}$ </h2><h2> $\large\text{= 8 + 1 - (-3) + 4(2)}$ </h2><h2> $\large\text{= 9 - (-3) + 4(2)}$ </h2><h2> $\large\text{= 12 + 4(2)}$ </h2><h2> $\large\text{= 12 + 8}$ </h2><h2> $\large\text{= 20}$ </h2><h2 /><h3> $\large\boxed{\textsf{Therefore, your answer is: \rm{20}}}\huge\checkmark$ </h3><h3> $\mathsf{Good \ luck \ on \ your \ assignment \ and \ enjoy \ your \ day!}$ </h3><h3 /><h3> $\frak{Amphitrite1040:)}$ </h3>

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The variable x represents a value in the set {4,6,7,8}.

olya-2409 [2.1K]

Answer:

B:6

Step-by-step explanation:

2(6-4)+3=7

2(2)+3=7

4+3=7

7=7

True

8 0

3 years ago

Match the parabolas represented by the equations with their foci.

Elenna [48]

Function 1 $f(x)=- x^{2} +4x+8$

First step: Finding when $f(x)$ is minimum/maximum
The function has a negative value $x^{2}$ hence the $f(x)$ has a maximum value which happens when $x=- \frac{b}{2a}=- \frac{4}{(2)(1)}=2$ . The foci of this parabola lies on $x=2$ .

Second step: Find the value of y-coordinate by substituting $x=2$ into $f(x)$ which give $y=- (2)^{2} +4(2)+8=12$

Third step: Find the distance of the foci from the y-coordinate
$y=- x^{2} +4x+8$ - Multiply all term by -1 to get a positive $x^{2}$
$-y= x^{2} -4x-8$ - then manipulate the constant of y to get a multiply of 4
$4(- \frac{1}{4})y= x^{2} -4x-8$
So the distance of focus is 0.25 to the south of y-coordinates of the maximum, which is $12- \frac{1}{4}=11.75$

Hence the coordinate of the foci is (2, 11.75)

Function 2: $f(x)= 2x^{2}+16x+18$

The function has a positive $x^{2}$ so it has a minimum

First step - $x=- \frac{b}{2a}=- \frac{16}{(2)(2)}=-4$
Second step - $y=2(-4)^{2}+16(-4)+18=-14$
Third step - Manipulating $f(x)$ to leave $x^{2}$ with constant of 1
$y=2 x^{2} +16x+18$ - Divide all terms by 2
$\frac{1}{2}y= x^{2} +8x+9$ - Manipulate the constant of y to get a multiply of 4
$4( \frac{1}{8}y= x^{2} +8x+9$

So the distance of focus from y-coordinate is $\frac{1}{8}$ to the north of $y=-14$
Hence the coordinate of foci is (-4, -14+0.125) = (-4, -13.875)

Function 3: $f(x)=-2 x^{2} +5x+14$

First step: the function's maximum value happens when $x=- \frac{b}{2a}=- \frac{5}{(-2)(2)}= \frac{5}{4}=1.25$
Second step: $y=-2(1.25)^{2}+5(1.25)+14=17.125$
Third step: Manipulating $f(x)$
$y=-2 x^{2} +5x+14$ - Divide all terms by -2
$-2y= x^{2} -2.5x-7$ - Manipulate coefficient of y to get a multiply of 4
$4(- \frac{1}{8})y= x^{2} -2.5x-7$
So the distance of the foci from the y-coordinate is - $\frac{1}{8}$ south to y-coordinate

Hence the coordinate of foci is (1.25, 17)

Function 4: following the steps above, the maximum value is when $x=8.5$ and $y=79.25$ . The distance from y-coordinate is 0.25 to the south of y-coordinate, hence the coordinate of foci is (8.5, 79.25-0.25)=(8.5,79)

Function 5: the minimum value of the function is when $x=-2.75$ and $y=-10.125$ . Manipulating coefficient of y, the distance of foci from y-coordinate is $\frac{1}{8}$ to the north. Hence the coordinate of the foci is (-2.75, -10.125+0.125)=(-2.75, -10)

Function 6: The maximum value happens when $x=1.5$ and $y=9.5$ . The distance of the foci from the y-coordinate is $\frac{1}{8}$ to the south. Hence the coordinate of foci is (1.5, 9.5-0.125)=(1.5, 9.375)

8 0

3 years ago

Two college roommates have each committed to donating to charity each week for the next year. The roommates’ weekly incomes are

schepotkina [342]

Answer:

C. 5 weeks.

Step-by-step explanation:

In this question we have a random variable that is equal to the sum of two normal-distributed random variables.

If we have two random variables X and Y, both normally distributed, the sum will have this properties:

$S=X+Y\\\\\ \mu_S=\mu_X+\mu_Y=30+60=90\\\\\sigma_S=\sqrt{\sigma_X^2+\sigma_Y^2}=\sqrt{10^2+20^2}=\sqrt{100+400}=\sqrt{500}=22.36$