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3 years ago

Which of the following are solutions to the equation below? check all that apply 4x^2-81=0

Mathematics

2 answers:

Sonbull [250]3 years ago

8 0

Answer:9/2 and -9/2

Step-by-step explanation:

i just did it

seropon [69]3 years ago

3 0

Answer:

9/2

Step-by-step explanation:

$4 {x}^{2} = 81 \\ {x}^{2} = \frac{81}{4} \\ x = \frac{ \sqrt{81} }{ \sqrt{4} } \\ x = \frac{9}{2}$

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David and Eric each shot 6 arrows at the target shown. David shot 4 arrows into A and 2 into B. His score was 18 points. Eric sh

liq [111]

Lets write an equation for each guy's shots and score:
4A + 2B = 18
3A + 3B = 21
To solve we multiply the first equation by -3 and the second by 2:
-12A - 6B = -54
6A + 6B = 42
--------------------
-12A + 0 = -12
A = 1
to find B we substitute in the first equation:
4A + 2B = 18
4(1) + 2B = 18
4 + 2B = 18
2B = 14
B = 7
therefore there were given 7 points in an arrow in B

3 0

3 years ago

Alan made a small four sided table for his office .Two sides of the table are 27 inches long and 36 inches long .If the diagonal

Tcecarenko [31]

Answer:

does NOT have right angles at the corners

Step-by-step explanation:

we are given that the sides of a table are 27" and 36" long.

If we assume the table to be rectangular, then by Pythagorean formula, we can find the diagonal and compare it to the 40" that we are given.

(refer to attached)

diagonal² = 27² + 36²

diagonal² = 2025

diagonal = √2025

diagonal = 45 inches

because the diagonal that we found is not the same as the 40" that was given, we can conclude that the table is not a rectangle (i.e does not have right angles at the corners)

6 0

3 years ago

Assume the amount you can spend on car payments is 50% of your monthly surplus.

nikdorinn [45]

773.77*0.5=386.88 hope i helped

4 0

3 years ago

According to a study conducted by the Gallup Organization, the the proportion of Americans who are afraid to fly is 0.10. A rand

notsponge [240]

Answer: 0.1457

Step-by-step explanation:

Let p be the population proportion.

Given: The proportion of Americans who are afraid to fly is 0.10.

i.e. p= 0.10

Sample size : n= 1100

Sample proportion of Americans who are afraid to fly = $\hat{p}=\dfrac{121}{1100}=0.11$

We assume that the population is normally distributed

Now, the probability that the sample proportion is more than 0.11:

$P(\hat{p}>0.11)=P(\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}>\dfrac{0.11-0.10}{\sqrt{\dfrac{0.10(0.90)}{1100}}})\\\\=P(z>\dfrac{0.01}{0.0090453})\ \ \ [\because z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}} ]\\\\=P(z>1.1055)\\\\=1-P(z\leq1.055)\\\\=1-0.8543=0.1457\ \ \ [\text{using z-table}]$

Hence, the probability that the sample proportion is more than 0.11 = 0.1457

3 0

3 years ago

Please help me with number #3 and check if the others are correct please I really need help

Sveta_85 [38]

All I can say is 1 and 2 are correct.

6 0

3 years ago