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igomit [66]
3 years ago
7

What number must be added to x^2+6x+7 to form a perfect square

Mathematics
1 answer:
RSB [31]3 years ago
7 0
Let the number be k,

Then adding to the expression we have,

{x}^{2}  + 6x + 7 + k
For this to be a perfect square, the discriminant must be zero.

We have,

a=1, b=6, c=7+k


{b}^{2}  - 4ac = 0

This implies that

{6}^{2}  - 4(1)(7 +k ) = 0
36 - 28 - 4k = 0
8 - 4k = 0
8 = 4k
k = 2
hence the number to be added is 2
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A painter used 1 1/2 gallons of paint to paint 3/4 of a room. At this same rate, how many gallons will it take to paint the whol
Luda [366]

Answer:

Convert to decimals:

1.5 and 0.75

Then, set up a proportion

1.5/0.75=x/1

proportion x/y=x/y

since the 3/4 and 1 are the same topic ( the room) we put them together.

Solve: 1.5/0.75=x

x=2

So 2 gallons

Hope this helps plz hit the crown :D

6 0
3 years ago
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Centimeters and meters size of window
Gnom [1K]

Answer:

Tiff, hon, just measure a window, your wasting your time

Step-by-step explanation:

7 0
3 years ago
Verify that the points are the vertices of a parallelogram and find its area. (2,-1,1), (5, 1,4), (0,1,1), (3,3,4)
Gelneren [198K]

Answer:

Area = 13.15 square units

Step-by-step explanation:

Let the given vertices be represented as follows:

A(2, -1, 1) = 2i - j + k

B(5, 1, 4) = 5i + j + 4k

C(0, 1, 1) = 0i + j + k

D(3, 3, 4) = 3i + 3j + 4k

(i) Let's calculate the vectors of all the sides:

\\AB = B - A =  (5i + j + 4k) - (2i - j + k)

AB = 5i + j + 4k - 2i + j - k                 [Collect like terms]

AB = 3i + 2j + 3k

BC = C - B =  (0i + j + k) - (5i + j + 4k)

BC = 0i + j + k - 5i - j - 4k                 [Collect like terms]

BC = -5i + 0j - 3k

CD = D - C =  (3i + 3j + 4k) - (0i + j + k)

CD = 3i + 3j + 4k - 0i - j - k                [Collect like terms]

CD = 3i + 2j + 3k

DA = A - D =  (2i - j + k) - (3i + 3j + 4k)

DA = 2i - j + k - 3i - 3j - 4k                [Collect like terms]

DA = -i - 4j - 3k

AC = C - A =  (0i + j + k) - (2i - j + k)

AC = 0i + j + k - 2i + j - k                [Collect like terms]

AC = -2i + 2j

BD = D - B = (3i + 3j + 4k) - (5i + j + 4k)

BD = 3i + 3j + 4k - 5i - j - 4k                [Collect like terms]

BD = -2i + 2j

(ii) From the results in (i) above, we can deduce that;

AB = CD This implies that AB || CD  [AB is parallel to CD]

AC = BD This implies that AC || BD  [AC is parallel to BD]

(iii) Therefore, ABDC is a parallelogram since opposite sides (AB and CD) are parallel. Hence, the points are vertices of a parallelogram

<u>Now let's calculate the area</u>

To find the area of the parallelogram, we find the magnitude of the cross product of any two adjacent sides.

In this case, we'll choose AB and AC

Area = |AB X AC|

Where;

AB X AC = \left[\begin{array}{ccc}i&j&k\\3&2&3\\-2&2&0\end{array}\right]

<u></u>

AB X AC = i(0 - 6) - j(0 + 6) + k(6 + 4)

AB X AC = - 6i - 6j + 10k

|AB X AC| = \sqrt{(-6)^2 + (-6)^2 + (10)^2}

|AB X AC| = \sqrt{172}

|AB X AC| = 13.15

Area = 13.15 square units.

<u></u>

<u></u>

<u>PS: </u> ACBD is also a parallelogram. The diagram has also been attached to this response.

6 0
2 years ago
A random sample of 144 recent donations at a certain blood bank reveals that 81 were type A blood. Does this suggest that the ac
Reptile [31]

Answer:

Null hypothesis:p=0.4  

Alternative hypothesis:p \neq 0.4

z=\frac{0.5625 -0.4}{\sqrt{\frac{0.4(1-0.4)}{144}}}=3.98  

p_v =2*P(z>3.98)=0.0000689  

Since the p value is very low compared to the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true percent of people with type A of blood is significantly different from 0.4 or 40%

Step-by-step explanation:

Information given

n=144 represent the random sample taken

X=81 represent the number of people with type A blood

\hat p=\frac{81}{144}=0.5625 estimated proportion of  people with type A blood

p_o=0.4 is the value that we want to verify

\alpha=0.01 represent the significance level

z would represent the statistic

p_v{/tex} represent the p value Hypothesis to testWe want to test if the percentage of the population having type A blood is different from 40%.:  Null hypothesis:[tex]p=0.4  

Alternative hypothesis:p \neq 0.4  

the statistic is given by:

z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}} (1)  

Replacing the info given we got:

z=\frac{0.5625 -0.4}{\sqrt{\frac{0.4(1-0.4)}{144}}}=3.98  

Now we can calculate the p value with this probability taking in count the alternative hypothesis:

p_v =2*P(z>3.98)=0.0000689  

Since the p value is very low compared to the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true percent of people with type A of blood is significantly different from 0.4 or 40%

3 0
3 years ago
What is the solution of the equation?
nadya68 [22]

Answer:

q = 4

Fully simplifying this equation gives you answer (A) q = 4

Hope this helps!

8 0
2 years ago
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