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2 years ago

The points (3,9) and (-3,-9) are plotted on the coordinate plane using the equation y= a•x. What is the value of a?

Mathematics

1 answer:

8_murik_8 [283]2 years ago

5 0

A=3

The equation y=3x goes through both points

Hope I helped

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Find the sample size required to achieve the given margin of error with SD = 51.02 and z - score = 1.96. Round your answer to th

coldgirl [10]

Answer:

The sample size required is 2500.

Step-by-step explanation:

z-score:

In function of the margin of error M, the z-score is given by:

$Z = \frac{M}{\frac{\sigma}{\sqrt{n}}} = \frac{M\sqrt{n}}{\sigma}$

In this question, we have that:

$\sigma = 51.02, M = 2, Z = 1.96$

$Z = \frac{M\sqrt{n}}{\sigma}$

$1.96 = \frac{2\sqrt{n}}{51.02}$

$2\sqrt{n} = 51.02*1.96$

$\sqrt{n} = \frac{51.02*1.96}{2}$

$(\sqrt{n})^2 = (\frac{51.02*1.96}{2})^2$

$n = 2500$

The sample size required is 2500.

3 0

2 years ago

There are two values of a for which the equation 5x2+ax+7x+5=0 has only one solution for x. What is the sum of those values of a

JulsSmile [24]

Answer:

-14

Step-by-step explanation:

First of all, we know that 5x^2+ ax+7x +5=0 only has one root. That means that b^2 - 4ac=0, and we can use this to find the discriminant, ax + 7x.

Now, if we simplified 5x^2+ ax+7x +5=0, by dividing it all by 5, it would be x^2+(a+7)/5x + 1 = 0.

After, we can plug what we know into the formula, b^2 - 4ac=0. It would be:

(a+7)^2 / 25 - 4 = 0

(a+7)^2 / 25 = 4

(a+7)^2 = 100

Since this is a square root, a+7 can be both negative or positive.

a+7= 10, or a+7 = -10

a=3, or a=-17

The question asks for the sum of a, which is 3 + (-17) = -14

Therefore, the answer is -14.

:) have fun with your rsm problems, assuming you got this from the portal.

7 0

2 years ago

What is 1,200,354,226,320 divided by 666,222,346

aleksklad [387]

1,200,354,226,320 divided by 666,222,346 is 1801.73216

6 0

3 years ago

Read 2 more answers

There are 132 counters in a bag. The ratio of green counters to purple

DedPeter [7]

9514 1404 393

Answer:

77 purple counters

Step-by-step explanation:

There are a total of 5+7=12 ratio units, so each stands for 132/12 = 11 counters. The 7 ratio units representing the purple counters stand for ...

11 × 7 = 77 purple counters

4 0

2 years ago

You bike 1 mile the first day of your training, 1.3 miles the second day, 1.9 miles the third day, and 3.1 miles the fourth d

JulsSmile [24]

Answer:

19.9 miles

Step-by-step explanation:

In this problem we have:

$d_1=1 mi$ is the distance travelled during the 1st day

$d_2=1.3 mi$ is the distance travelled during the 2nd day

$d_3=1.9 mi$ is the distance travelled during the 3rd day

$d_4=3.1 mi$ is the distance travelled during the 4th day

We notice that the difference between the distance travelled on the (n+1)-th day and the distance travelled on the n-th day doubles every day. In fact:

$d_2-d_1=0.3\\d_3-d_2=2\cdot 0.3 = 0.6\\d_4-d_3=2\cdot 0.6 = 1.2$

Which can be rewritten using the general formula:

$d_{n+1}-d_n=2(d_n-d_{n-1})$

This means that

$d_{n+1}=d_n+2(d_n-d_{n-1})$

By applying this formula recursively, we can find the 7th term, which is the distance travelled on the 7th day:

$d_1=1\\d_2=1.3\\d_3=1.9\\d_4=3.1\\d_5=3.1+2\cdot 1.2=5.5\\d_6=5.5+2\cdot 2.4=10.3\\d_7=10.3+2\cdot 4.8=19.9 mi$

So, the distance travelled on the 7th day is 19.9 miles.

7 0

3 years ago