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1 year ago

Julio wants to solve the system shown using the elimination method. Which is the best way to begin?

Mathematics

1 answer:

ElenaW [278]1 year ago

4 0

Answer:

B. Multiply each term in x - 12y = 2 by 4 and add it to the other original equation.

Step-by-step explanation:

The expression are two linear equation and can be solved simultaneously

$x - 12y = 2------------------1$

$-4x + 7y = 12----------------------2$

1. we need to multiply each term in eqn 1 by 4 and add it to the other

original equation(2).

$4x - 48y = 8----------------3\\-4x + 7y = 12---------------2\\\\$

Adding both 3 and 2 we have

$4x - 48y = 8----------------3\\-4x + 7y = 12---------------2\\\\\\$

2. once we have gotten the value of y

we then substitute it in any of the equations to solve for x

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Two window washers start at the heights shown. (A: 21 ft high rising 8 in per second. The other is 50 feet high descending 11inc

babunello [35]

For this case, the first thing we are going to do is write the generic equation of motion for the vertical axis.

We have then:

$h = \frac {1} {2} gt ^ 2 + vo * t + h0$

Where,

g: acceleration of gravity
vo: initial speed
h0: initial height

For the first body:

$h1 = \frac {1} {2} gt ^ 2 + \frac {8} {12} * t + 21$

For the second body:

$h2 = \frac {1} {2} gt ^ 2 - \frac {11} {12} * t + 50$

By the time both bodies have the same height we have:

$h1 = h2\\$

$\frac {1} {2} gt ^ 2 + \frac {8} {12} * t + 21 = \frac {1} {2} gt ^ 2 - \frac {11} {12} * t + 50$

Rewriting we have:

$\frac {8} {12} * t + 21 = - \frac {11} {12} * t + 50$

$\frac {8} {12} * t + \frac {11} {12} * t = 50 - 21$

$\frac {19} {12} * t = 29$

Clearing time:

$t = 29 (\frac {12} {19})\\t = 18.31s$

Answer:

it takes 18.31s for the two window washers to reach the same height

6 0

2 years ago

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Jackson has ten dollar bills and one dollar bills in his pocket. The number of ten dollar bills is five more than six times the

Katyanochek1 [597]

Answer:

Let t be the number of ten dollar bills.

o×6+5=t

If you need it without t, then it's:

o×6+5

Step-by-step explanation:

Let t be the number of ten dollar bills.

o×6+5=t

We get this because the question said that there were more ten-dollar bills than 6 times the number of one-dollar bills.

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1 year ago

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

antiseptic1488 [7]

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.

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1 year ago

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Kelly asked some of her classmates how many hours of sleep they get on school nights. Here are the results:

Hitman42 [59]

All three are equal to 8

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1 year ago

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After calculating the sample size needed to estimate a population proportion to within 0.05, you have been told that the maximum

Svetlanka [38]

Answer: 40000

Step-by-step explanation:

The formula to find the sample size is given by :-

$n=p(1-p)(\dfrac{z_{\alpha/2}}{E})^2$ , where p is the prior estimate of the population proportion.

Here we can see that the sample size is inversely proportion withe square of margin of error.

i.e. $n\ \alpha\ \dfrac{1}{E^2}$

By the equation inverse variation, we have

$n_1E_1^2=n_2E_2^2$

Given : $E_1=0.05$ $n_1=1000$

$E_2=0.025$

Then, we have

$(1000)(0.05)^2=n_2(0.025)^2\\\\\Rightarrow\ 2.5=0.000625n_2\\\\\Rightarrow\ n_2=\dfrac{2.5}{0.000625}=4000$

Hence, the sample size will now have to be 4000.

6 0

1 year ago