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2 years ago

Hence explain how you know that x^2-8x+20 is always positive

Mathematics

2 answers:

Tasya [4]2 years ago

6 0

If you complete the square you get

${(x - 4) }^{2} + 4$

and as any number squared is positive and 4 is positive, the result must be positive

Leya [2.2K]2 years ago

6 0

Answer:

x^2-8x+20=x^2-2*x*4+4^2+4=(x-4)^2+4

so (x-4)^2 is positive or zero (but +4 is always positive)

Step-by-step explanation:

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Stu hiked a trail at an average rate of 3 miles per hour. He ran back on the same trail at an average rate of 5 miles per hour.

Andrews [41]

3t = 5(3-t)
3t = 15 - 5t
3t + 5t = 15
8t = 15
t = 15/8
t = 1 7/8

7/8 * 60 mins = 52.50 minutes

t = 1 hour and 52.5 minutes

It took Stu 1 hour and 52.5 minutes to hike the trail one way.

3 0

2 years ago

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For each system of equations, drag the true statement about its solution set to the box under the system?

natta225 [31]

Answer:

y = 4x + 2

y = 2(2x - 1)

Zero solutions.

4x + 2 can never be equal to 4x - 2

y = 3x - 4

y = 2x + 2

One solution

3x - 4 = 2x + 2 has one solution

Step-by-step explanation:

* Lets explain how to solve the problem

- The system of equation has zero number of solution if the coefficients

of x and y are the same and the numerical terms are different

- The system of equation has infinity many solutions if the

coefficients of x and y are the same and the numerical terms

are the same

- The system of equation has one solution if at least one of the

coefficient of x and y are different

* Lets solve the problem

∵ y = 4x + 2 ⇒ (1)

∵ y = 2(2x - 1) ⇒ (2)

- Lets simplify equation (2) by multiplying the bracket by 2

∴ y = 4x - 2

- The two equations have same coefficient of y and x and different

numerical terms

∴ They have zero equation

y = 4x + 2

y = 2(2x - 1)

Zero solutions.

4x + 2 can never be equal to 4x - 2

∵ y = 3x - 4 ⇒ (1)

∵ y = 2x + 2 ⇒ (2)

- The coefficients of x and y are different, then there is one solution

- Equate equations (1) and (2)

∴ 3x - 4 = 2x + 2

- Subtract 2x from both sides

∴ x - 4 = 2

- Add 4 to both sides

∴ x = 6

- Substitute the value of x in equation (1) or (2) to find y

∴ y = 2(6) + 2

∴ y = 12 + 2 = 14

∴ y = 14

∴ The solution is (6 , 14)

y = 3x - 4

y = 2x + 2

One solution

3x - 4 = 2x + 2 has one solution

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2 years ago

The total number of degrees, D, in an n-sided polygon is given by the formula D=180(n-2). When Janelle solves for n, she gets n=

Rus_ich [418]

<span>D = 180 * (n -2)
D = 180n -360
180n = D +360
n = (D / 180) + 2

So, the answer is "A"
And we can test this with a square, sum of angles = 360
n = (D / 180) +2
n = (360 / 180) +2
number of sides = 4
correct

Source:
http://www.1728.org/polygon.htm

</span>

3 0

1 year ago

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Find A ∩ B if A = {2, 5, 8, 11, 14} and B = {1, 3, 5, 7}.

Gwar [14]

Answer:

Step-by-step explanation:

$A=\{2,\ 5,\ 8,\ 11,\ 14\}\\\\B=\{1,\ 3,\ 5,\ 7\}\\\\A\ \cap\ B-\text{the intersection of two sets A and B,}\\\text{ is the set that contains all elements of A that also belong to B.}\\\\\text{Therefore:}\ A\ \cap\ B=\{5\}$

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2 years ago

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A new obstacle course is home to several new types of challenging obstacles. One such obstacle is traversing a 15-stair staircas

Tresset [83]

Answer: $22\frac{1}{2}\text{ Feet}$

Step-by-step explanation:

Here, the vertical space between two consecutive stairs in first 10 stairs = $1\frac{1}{3}\text{ feet}$

⇒ The total vertical distance for 10 stairs = $10\times 1\frac{1}{3}=10\times \frac{4}{3}=\frac{40}{3}\text{ feet}$

Also, The vertical space between two consecutive stairs for last 5 stairs = $1\frac{3}{4}\text{ feet}$

⇒ The total vertical distance for 10 stairs = $10\times 1\frac{1}{3}=5\times \frac{7}{4}=\frac{35}{4}\text{ feet}$

Thus, The total vertical distance = Total vertical space for the first 10 stairs + Total vertical space for the last 5 stairs

= $\frac{40}{3} + \frac{35}{4}$

= $\frac{160+105}{12}$

= $\frac{265}{12}$

= $22\frac{1}{2}\text{ Feet}$

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2 years ago