can someone just explain how solve a system of linear equation by substitution pleaseee in need of helpp

1. If you are asked to use elimination to solve for x", what do you need to multiply the bottom equation by to eliminate "y?

hram777 [196]

Answer:

-5

Step-by-step explanation:

There is different ways to solve methods of elimination but if you wanted to cancel y out you would multiply by the opposite sign....for example

7x + 5y = 19

-5 (2x + y = 19) ---> -10x -5y = 95

this would cancel out your y to solve for x so you can plug it back in and solve! hope this helps!!!

6 0

3 years ago

] It is claimed that 42% of US college graduates had a mentor in college. For a sample of college graduates in Colorado, it was

Bad White [126]

Answer:

$z=\frac{0.480 -0.42}{\sqrt{\frac{0.42(1-0.42)}{1045}}}=3.930$

The p value for this case would be given by:

$p_v =P(z>3.930)=0.0000443$

For this case the p value is lower than the significance level so then we have enough evidence to reject the null hypothesis so then we can conclude that the true proportion is significantly higher than 0.42

Step-by-step explanation:

Information given

n=1045 represent the random sample selected

X=502 represent the college graduates with a mentor

$\hat p=\frac{502}{1045}=0.480$ estimated proportion of college graduates with a mentor

$p_o=0.42$ is the value that we want to test

z would represent the statistic

$p_v$ represent the p value

Hypothesis to test

We want to test if the true proportion is higher than 0.42, the system of hypothesis are.:

Null hypothesis: $p \leq 0.42$

Alternative hypothesis: $p > 0.42$

The statistic is given by:

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

Replacing the info we got:

$z=\frac{0.480 -0.42}{\sqrt{\frac{0.42(1-0.42)}{1045}}}=3.930$

The p value for this case would be given by:

$p_v =P(z>3.930)=0.0000443$

For this case the p value is lower than the significance level so then we have enough evidence to reject the null hypothesis so then we can conclude that the true proportion is significantly higher than 0.42

7 0

3 years ago

Find the volume of the frog queen building in Graz, Austria. The building is 18 meters long, 17 meters tall, and 18 meters wide

densk [106]

Answer: 5,508 m3

Step-by-step explanation: V= 18 x 17 x 18 = 5,508 m3

8 0

3 years ago

Read 2 more answers

What’s the equivalent expression

r-ruslan [8.4K]

Answer:

9 (2 a - 3)^2

Step-by-step explanation:

Simplify the following:

(6 a - 9)^2

Hint: | Factor out the greatest common divisor of the coefficients of 6 a - 9.

Factor 3 out of 6 a - 9:

(3 (2 a - 3))^2

Hint: | Distribute exponents over products in (3 (2 a - 3))^2.

Multiply each exponent in 3 (2 a - 3) by 2:

3^2 (2 a - 3)^2

Hint: | Evaluate 3^2.

3^2 = 9:

Answer: 9 (2 a - 3)^2

4 0

3 years ago

Sally is standing at one corner of a snowy rectangular field that measures 200 ft by 200 ft. She wishes toreach a warm cabin loc

pshichka [43]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The optimal point(i.e the position of P) that will allow Sally to reach the cabin as quickly as possible is $d = 50 \ ft$ from the cabin.

Step-by-step explanation:

From the question we are told that

The speed from the point Sally is standing to the point P is $u = 3 \ ft /s$

The speed from the point P to the cabin is $v = 5 \ ft /s$

Let denote the distance from the bottom left corner to the P be y ft

Generally according to Pythagoras theorem the distance from Sally's first position to point P is mathematically represented as

$s = \sqrt{y^2 + 200^2}$

Generally the distance from that point P to the cabin is mathematically represented as

$d = 200 -y$

Generally the time it takes Sally to cover that distance s is mathematically represented as

$t_1 = \frac{s}{u}$

=> $t_1 = \frac{ \sqrt{y^2 + 200^2}}{3}$

Generally the time it takes Sally to cover that distance d is mathematically represented as

$t_2 = \frac{d}{v}$

=> $t_2 = \frac{ 200 - y }{5}$

So the total time taken is

$t= \frac{ \sqrt{y^2 + 200^2}}{3} + \frac{ 200 - y }{5}$

Generally the minimum time taken with respect to the distance is mathematically evaluated by differentiating and equating the derivative to 0

So

$\frac{dt}{dy} =\frac{1}{3} \frac{y}{ \sqrt{y^2 + 200^2} } - \frac{1}{5} =0$

=> $\frac{dt}{dy} = \frac{y^2 }{y^2 + 200 ^2} =\frac{9}{25}$

=> $25y^2 = 9y^2 + 9 * 200^2$

=> $16y^2 = 360000$

=> $y = 150$

So the distance from point P to the cabin is

$d = 200 -150$

=> $d = 50 \ ft$

So the optimal point(i.e the position of P) that will allow Sally to reach the cabin as quickly as possible is $d = 50 \ ft$ from the cabin

8 0

3 years ago

can someone just explain how solve a system of linear equation by substitution pleaseee in need of helpp​

can someone just explain how solve a system of linear equation by substitution pleaseee in need of helpp