Eight times the sum of a number and 20 is at most −25

I need help with math please

Dennis_Churaev [7]

Answer:

47/30

Step-by-step explanation:

2.35 * 2/3 =

= 2 35/100 * 2/3

= 2 7/20 * 2/3

= 47/20 * 2/3

= 94/60

= 47/30

5 0

3 years ago

Find the surface area of this cube. Be sure to include the correct unit in your answer.

Alexxx [7]

Answer:

486 cm

Step-by-step explanation:

9×9=81

there are 6 faces

81×6=486

7 0

2 years ago

Find all values of c such that c/(c - 5) = 4/(c - 4). If you find more than one solution, then list the solutions you find separ

Deffense [45]

Answer:

$\large\boxed{\bold{NO\ REAL\ SOLUTIONS}}\\\boxed{x=4-2i,\ x=4+2i}$

Step-by-step explanation:

$Domain:\\c-4\neq0\ \wedge\ c-5\neq0\Rightarrow c\neq4\ \wedge\ c\neq5\\\\\dfrac{c}{c-5}=\dfrac{4}{c-4}\qquad\text{cross multiply}\\\\c(c-4)=4(c-5)\qquad\text{use the distributive property}\\\\c^2-4c=4c-20\qquad\text{subtract}\ 4c\ \text{from both sides}\\\\c^2-8c=-20\qquad\text{add 20 to both sides}\\\\c^2-8c+20=0\qquad\text{use the quadratic formula}$

$\text{for}\ ax^2+bx+c=0\\\\\text{if}\ b^2-4ac0,\ \text{then the equation has two solutions}\ x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$

$x^2-8x+20=0\\\\a=1,\ b=-8,\ c=20\\\\b^2-4ac=(-8)^2-4(1)(20)=64-80=-16$

$\text{In the set of complex numbers:}\\\\i=\sqrt{-1}\\\\\text{therefore}\ \sqrt{b^2-4ac}=\sqrt{-16}=\sqrt{(16)(-1)}=\sqrt{16}\cdot\sqrt{-1}=4i\\\\x=\dfrac{-(-8)\pm4i}{2(1)}=\dfrac{8\pm4i}{2}=\dfrac{8}{2}\pm\dfrac{4i}{2}=4\pm2i$

6 0

3 years ago

Read 2 more answers

Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 + 2x = 17

yawa3891 [41]

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Equation Given
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x² + 2x = 17

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Add the constant to make it perfect square
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x² + 2x + (2/2)² - ²(2/2)² = 17

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Evaluate the brackets
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x² + 2x + (1)² - ²(1)² = 17

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Form the perfect square
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(x + 1)² - 1 = 17

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Add 1 to both sides
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(x + 1)² = 17 + 1
(x + 1)² = 18

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Square root both sides
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√(x + 1)² = $\pm$ √18

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Solve for x
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x = 4.24 - 1 or - 4.24 -1

x = 3.24 or - 5.24 (nearest hundredth)

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Answer: x = x = 3.24 or - 5.24
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7 0

3 years ago

Which of the following equations best models the data plotted below?

ICE Princess25 [194]

The key with these problems is to find which function has the closest y-intercept to the graph, and then try to figure out which one best approximates the slope.
Here are our options:
<span>A. y = x + 4
B. y = 4x + 9
C. y = x + 18
D. y = 3x + 22

Which has the closest approximation of the y-intercept?
The y-intercept is not directly given, but we can assume it is less than 10.
That leaves us with A and B.

Which has the closest approximation of the slope?
The graph, on average, seems to move up about 60 and over about 15.
Slope = rise/run = 60/15 = 4. Although the slope isn't exactly 4, it's much closer to 4 than 1, which is slope for option A.

Therefore, the answer is
B) y= 4x + 9

</span>

6 0

3 years ago