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3 years ago

0.4x + 6.1, x= -5. (show work)

2 answers:

Elena-2011 [213]3 years ago

8 0

0.4
x
+
6.1
x
=
−
5
Step 1: Simplify both sides of the equation.
0.4
x
+
6.1
x
=
−
5
(
0.4
x
+
6.1
x
)
=
−
5
(Combine Like Terms)
6.5
x
=
−
5
6.5
x
=
−
5
Step 2: Divide both sides by 6.5.
6.5
x
6.5
=
−
5
6.5 x
=
−
0.769231

yan [13]3 years ago

3 0

Answer:

4.1

Step-by-step explanation:

0.4(-5)+6.1

0.4 times -5 is -2

-2 +6.1 = 4.1

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How many solutions are there for the system x^2+4y^2=100 and 4y-x^2=-20

never [62]

There are 5 solutions for this system.

x^2 + 4y^2 = 100 ____1
4y - x^2 = -20 ____2
Add both 1 & 2 together. x^2 gets cancelled
4y^2 + 4y = 80 (send 80 to the other side and divide by 4)
Then equation the becomes : y^2 + y -20 =0
Now factorise the equation: (y+5) (y-4) = 0
Solve for y : y = -5 and y = 4
Using the values of y to find the values of x. From equation 1:
x^2 = 100 - 4y^2 x = /100 - 4y^2 (/ means square root) Replace values of y
y = -5, x = /100 - 4(-5)^2 = /100 - 100 = 0
y = 4, x = /100 - 4(4)^2 = / 100 - 64 = /36 = -6 or 6
Thus we have 6 solutions y = -5, 4 and x = -6, 0, 6

6 0

3 years ago

Log(x-2)+log2=2logy log(x-3y+3)=0

In-s [12.5K]

Answer:

Step-by-step explanation:

$\left\{\begin{array}{ccc}\log(x-2)+\log2=2\log y&(1)\\\log(x-3y+3)=0&(2)\end{array}\right$

$===========================\\\text{DOMAIN:}\\\\x-2>0\to x>2\\y>0\\x-3y+3>0\to x-3y>-3\\=====================\\\\\text{We know:}\ \log_ab=c\iff a^c=b,\\\\\text{therefore}\ \log_ab=0\iff a^0=b\to b=1\\\\\text{From this we have}\\\\\log(x-3y+3)=0\iff x-3y+3=1\qquad\text{add}\ 3y\ \text{to both sides}\\\\x+3=3y+1\qquad\text{subtract 3 from both isdes}\\\\\boxed{x=3y-2}\qquad(*)\\\\\text{Substitute it to (1)}$

$\log(3y-2-2)+\log2=2\log(y)\qquad\text{use}\ \log_ab^n=n\log_ab\\\\\log(3y-4)+\log2=\log(y^2)\qquad\text{subtract}\ \log(y^2)\ \text{from both sides}\\\\\log(3y-4)+\log2-\log(y^2)=0\\\\\text{Use}\ \log_ab+\log_ac=\log_a(bc)\ \text{and}\ \log_ab-\log_ac=\log_a\dfrac{b}{c}\\\\\log\dfrac{(3y-4)(2)}{y^2}=0\qquad\text{use}\ \log_ab=0\Rightarrow b=1\\\\\dfrac{(3y-4)(2)}{y^2}=1\iff y^2=(3y-4)(2)\\\\\text{Use the distributive property}\ a(b+c)=ab+ac$

$y^2=(3y)(2)+(-4)(2)\\\\y^2=6y-8\qquad\text{subtract}\ 6y\ \text{from both sides}\\\\y^2-6y=-8\qquad\text{add 8 to both sides}\\\\y^2-6y+8=0\\\\y^2-2y-4y+8=0\\\\y(y-2)-4(y-2)=0\\\\(y-2)(y-4)=0\iff y-2=0\ \vee\ y-4=0\\\\\boxed{y=2\ \vee\ y=4}\in D$

$\text{Put the values of}\ y\ \text{to }\ (*):\\\\\text{for}\ y=2:\\\\x=3(2)-2\\\\x=6-2\\\\\boxed{x=4}\in D\\\\\text{for}\ y=4:\\\\x=3(4)-2\\\\x=12-2\\\\\boxed{x=10}\in D$

4 0

3 years ago

genetic experiment with peas resulted in one sample of offspring that consisted of green peas and yellow peas. a. Construct a %

Andreas93 [3]

Complete Question

A genetic experiment with peas resulted in one sample of offspring that consisted of 432 green peas and 164 yellow peas. a. Construct a 95% confidence interval to estimate of the percentage of yellow peas. b. It was expected that 25% of the offspring peas would be yellow. Given that the percentage of offspring yellow peas is not 25%, do the results contradict expectations?

Answer:

The 95% confidence interval is $0.2392 < p < 0.3108$

No, the confidence interval includes 0.25, so the true percentage could easily equal 25%

Step-by-step explanation:

From the question we are told that

The total sample size is $n = 432 + 164 =596$

The number of offspring that is yellow peas is $y = 432$

The number of offspring that is green peas is $g = 164$

The sample proportion for offspring that are yellow peas is mathematically evaluated as

$\r p = \frac{ 164 }{596}$

$\r p = 0.275$

Given the the confidence level is 95% then the level of significance is mathematically represented as

$\alpha = (100 - 95)\%$

$\alpha = 5\% = 0.0 5$

The critical value of $\frac{\alpha }{2}$ from the normal distribution table is

$Z_{\frac{\alpha }{2} } = 1.96$

Generally the margin of error is mathematically evaluated as

$E = Z_{\frac{\alpha }{2} } * \sqrt{\frac{\r p (1- \r p )}{n} }$

=> $E = 1.96 * \sqrt{\frac{0.275 (1- 0.275 )}{596} }$

=> $E = 0.0358$

The 95% confidence interval is mathematically represented as

$\r p - E < p < \r p + E$

=> $0.275 - 0.0358 < p < 0.275 + 0.0358$

=> $0.2392 < p < 0.3108$

6 0

3 years ago

Nora and Lila are reading the same novel for book club.

stich3 [128]

Answer:

1. Nora and Lila be on the same page of the book after 6 days and a half.

2. Nora and Lila be on the page 180.

Step-by-step explanation:

1. Let's check the information given to resolve the question:

Current page of the novel that Nora is reading now = 128

Pages per day Nora reads = 8

Current page of the novel that Lila is reading now = 102

Pages per day Lila reads = 12

Days ahead for Nora and Lila will be on the same page = x

2. After how many days of reading will Nora and Lila be on the same page of the book?

128 + 8x = 102 + 12x

8x - 12x = 102 - 128 (Subtracting 12x and 128 at both sides)

-4x = -26

x = 6.5

Nora and Lila be on the same page of the book after 6 days and a half.

3. What page will they be on?

Nora : 128 + 8 (6.5) = 128 + 52 = 180

Lila : 102 + 12 (6.5) = 102 + 78 = 180

Nora and Lila be on the page 180

4 0

3 years ago

Work out the size of one of the exterior angles

hodyreva [135]

Given Information :-

⠀

A polygon with 10 sides ( Decagon )

⠀

To Find :-

⠀

The value of one of the exterior angles

⠀

Formula Used :-

⠀

$\qquad \diamond \: \underline{ \boxed{ \pink{ \sf Exterior ~angle = \dfrac {360^\circ}{no. ~of~sides}}}} \: \star$

⠀

Solution :-

⠀

Putting the given values, we get,

⠀

$\sf \dashrightarrow Exterior ~angle = \dfrac{360 ^\circ}{10} \: \: \\ \\ \\ \sf \dashrightarrow Exterior ~angle = \frac{36 \cancel{0}^\circ}{ \cancel{10}} \: \: \\ \\ \\ \sf \dashrightarrow Exterior ~angle = \underline{ \boxed{ \frak{ \red{36^\circ}}}} \: \star \\ \\$

Thus, the value of the exterior angles of a Decagon is 36°.

⠀

$\underline{ \rule{227pt}{2pt}} \\ \\$

8 0

2 years ago

Read 2 more answers