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alexdok [17]
1 year ago
8

Consider the system of linear equations. 5x+10y=15 10x+3y=13 To use the linear combination method and addition to eliminate the

x-terms, by which number should the first equation be multiplied?
A- -2
B- -1/2
C- 1/2
D- 2
Mathematics
2 answers:
antiseptic1488 [7]1 year ago
6 0

Answer:

  A:  -2

Step-by-step explanation:

You want some factor k such that k(5x) +(10x) = 0. That is, 5k+10 = 0. The solution to this is k=-2, corresponding to selection A.

vesna_86 [32]1 year ago
4 0

k = -2 for sure

I normally multiply 5x+10y=15 by -2 to cancel out the x's.

This is because you can only solve the problem if one of your variables is canceled out and then you solve!

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At the bank, Brent exchanges $50 in bills for 50 one-dollar coins. The total mass of the coins is 405 grams. ESTIMATE the mass o
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To find the answer, you should divide 405 by 50 to find the mass of one coin. The formula should look like this:
\frac{405}{50}
= 8.1
The exact mass is 8.1 grams, but because you want an estimate, the answer should be
About 8 grams for the mass of 1 one-dollar coin
4 0
2 years ago
Read 2 more answers
A company wants to establish that the mean life of its batteries, when used in a wireless mouse, is over 183 days. The data will
enyata [817]

Answer:

a) Null and alternative hypotheses are:

H_{0}: mu=183 days

H_{a}: mu>183 days

b) If the true mean is 190 days, Type II error can be made.

Step-by-step explanation:

Let mu be the mean life of the batteries of the company when it is used in a wireless mouse

Null and alternative hypotheses are:

H_{0}: mu=183 days

H_{a}: mu>183 days

Type II error happens if we fail to reject the null hypothesis, when actually the alternative hypothesis is true.

That is if we conclude that mean life of the batteries of the company when it is used in a wireless mouse is at most 183 days, but actually mean life is 190 hours, we make a Type II error.

4 0
2 years ago
Suppose that we've decided to test Clara, who works at the Psychic Center, to see if she really has psychic abilities. While tal
mixas84 [53]

Answer:

A) 3.5

B) 1.6202

Step-by-step explanation:

In binomial distribution,

E(X) = np and Var(X) = npq while

SD (X) = √(npq)

Where n is number of cards drawn

p is probability of getting one particular shape

q = 1-p

So from the question, n = 14

p = 13/52 = 1/4

q = 1-(1/4) = 3/4

So;

A) E(x) = np = 14 x 1/4 = 3.5

B) SD (X) = √(npq) = √(14 x 1/4 x 3/4) = √(42/16) = √2.625 = 1.6202

4 0
2 years ago
3,298,076 in expanded form
LekaFEV [45]
3,000,000+200,000+90,000+8,000+70+6
6 0
2 years ago
Show that b^2 is greater than equal to or less than ac, according as a, b, c are in A.P., G.P.
ValentinkaMS [17]

Answer/Step-by-step explanation  (ac > b² or b² < ac. )

A/c to question, we have to show:-

b² >ac in A.P ........ (1)

b² = ac in G.P .....(2)

b² < ac in H.P. ..... (3)

b = a+c/2 (A.P)

b = √ac ( G.P)

b = 2ac/a+c (H.P)

In A.P :

b² > ac = b² - ac

= (a+c/2)² - ac

= (a²+2ac+c²/4) - ac  = a² + 2ac + c² - 4ac / 4

= a² - 2ac + c² / 4  = ( a - c ) ² / 4 > 0  Hence, b²>ac

In G.P:-

b = √ac

Hence, b² = ac

In H.P :-  b² < ac = ac > b²  = ac - b²  = ac - ( 2ac / a+c)

= ac(a+c) - 2ac / a+c

= a²c + ac² - 2ac / a+c

= ac(2ac - 2) / a+c > 0

Hence, ac > b² or b² < ac.

5 0
1 year ago
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