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3 years ago

1) a) Factorize: G(x) = (x+5)2 – 3x(x+5).

Mathematics

1 answer:

Arada [10]3 years ago

8 0

Answer:

In bold.

Step-by-step explanation:

a. (x+5)^2 – 3x(x+5) x+5 is common

= (x + 5)(x + 5 - 3x)

= (x + 5)(5 - 2x)

b. (x + 5)(5 - 2x) = 0

x = -5, 2.5.

2a. Area of the square = (x + 5)^2

Area of triangle AEB

= 1/2 * base * height

I am assuming that H is the centre of AB , so

Area = x*x

= x^2.

6x^2 = (x + 5)^2

6x^2 = x^2 + 10x + 25

5x^2 - 10x - 25 = 0

x^2 - 2x - 5 = 0

x = [-(-2) +/- sqrt(2^2 - 4*1*-5)] / 2

x = -1.45, 3.45.

(we ignore the negative).

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James says,

Dima020 [189]

-3^3 = -27

Step-by-step explanation:

Thats because -3^3 is (-3×3×3) not (-3×-3×-3) which we are multiplying a the constant not the the powers

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3 years ago

Read 2 more answers

An experiment was conducted to observe the effect of an increase in temperature on the potency of an antibiotic. Three 1-ounce p

ludmilkaskok [199]

Answer:

a) $y=-0.317 x +46.02$

b) Figure attached

c) $S^2=\hat \sigma^2=MSE=\frac{190.33}{10}=19.03$

Step-by-step explanation:

We assume that th data is this one:

x: 30, 30, 30, 50, 50, 50, 70,70, 70,90,90,90

y: 38, 43, 29, 32, 26, 33, 19, 27, 23, 14, 19, 21.

a) Find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i = 30+30+30+50+50+50+70+70+70+90+90+90=720$

$\sum_{i=1}^n y_i =38+43+29+32+26+33+19+27+23+14+19+21=324$

$\sum_{i=1}^n x^2_i =30^2+30^2+30^2+50^2+50^2+50^2+70^2+70^2+70^2+90^2+90^2+90^2=49200$

$\sum_{i=1}^n y^2_i =38^2+43^2+29^2+32^2+26^2+33^2+19^2+27^2+23^2+14^2+19^2+21^2=9540$

$\sum_{i=1}^n x_i y_i =30*38+30*43+30*29+50*32+50*26+50*33+70*19+70*27+70*23+90*14+90*19+90*21=17540$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=49200-\frac{720^2}{12}=6000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=17540-\frac{720*324}{12}{12}=-1900$

And the slope would be:

$m=-\frac{1900}{6000}=-0.317$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{720}{12}=60$

$\bar y= \frac{\sum y_i}{n}=\frac{324}{12}=27$

And we can find the intercept using this:

$b=\bar y -m \bar x=27-(-0.317*60)=46.02$

So the line would be given by:

$y=-0.317 x +46.02$

b) Plot the points and graph the line as a check on your calculations.

For this case we can use excel and we got the figure attached as the result.

c) Calculate S^2

In oder to calculate S^2 we need to calculate the MSE, or the mean square error. And is given by this formula:

$MSE=\frac{SSE}{df_{E}}$

The degred of freedom for the error are given by:

$df_{E}=n-2=12-2=10$

We can calculate:

$S_{y}=\sum_{i=1}^n y^2_i -\frac{(\sum_{i=1}^n y_i)^2}{n}=9540-\frac{324^2}{12}=792$

And now we can calculate the sum of squares for the regression given by:

$SSR=\frac{S^2_{xy}}{S_{xx}}=\frac{(-1900)^2}{6000}=601.67$

We have that SST= SSR+SSE, and then SSE=SST-SSR= 792-601.67=190.33[/tex]

So then :

$S^2=\hat \sigma^2=MSE=\frac{190.33}{10}=19.03$

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3 years ago

B. If some amount of water contains 1400 oxygen atoms, how many hydrogen atoms does it contain?

Genrish500 [490]

Answer:

B: 2800 hydrogen atoms

C: 6760 hydrogen atoms

D: y=amount of oxygen atoms*2

Step-by-step explanation:

B: We know the formula for water is H2O. SO that means that there is 2 hydrogen atoms and 1 oxygen atom. So there is 2 times the amount of hydrogen atoms so we can do 1400*2=2800, So there is 2800 hydrogen atoms in the water.

C: Same thing as B. 3380*2=6760

D: y=amount of oxygen atoms*2. Because there is one oxygen atom and two hydrogen atoms so 1*2=2.

5 0

3 years ago

I'm given that log4=0.602 and log12=1.079

Rudiy27

log(3) = log(12/4)

Use the quotient rule [ $\text{log}_a\frac{x}{y}=log_ax-log_ay$ ] to simplify.

log(12/4) = log(12) - log(4)

Simplify using the given values for 12 and 4.

1.079 - 0.602

0.477

Therefore, log(12) ≈ 0.477

Best of Luck!

6 0

3 years ago

Read 2 more answers

PLEASE RESPOND! !!

cestrela7 [59]

Answer:

36/132

Step-by-step explanation:

36/132, .27, 27%...

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3 years ago