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3 years ago

Prove that the roots of x2+(1-k)x+k-3=0 are real for all real values of k

Mathematics

1 answer:

masha68 [24]3 years ago

6 0

Answer:

Roots are not real

Step-by-step explanation:

To prove : The roots of x^2 +(1-k)x+k-3=0x

+(1−k)x+k−3=0 are real for all real values of k ?

Solution :

The roots are real when discriminant is greater than equal to zero.

i.e. b^2-4ac\geq 0b

−4ac≥0

The quadratic equation x^2 +(1-k)x+k-3=0x

+(1−k)x+k−3=0

Here, a=1, b=1-k and c=k-3

Substitute the values,

We find the discriminant,

D=(1-k)^2-4(1)(k-3)D=(1−k)

−4(1)(k−3)

D=1+k^2-2k-4k+12D=1+k

−2k−4k+12

D=k^2-6k+13D=k

−6k+13

D=(k-(3+2i))(k+(3+2i))D=(k−(3+2i))(k+(3+2i))

For roots to be real, D ≥ 0

But the roots are imaginary therefore the roots of the given equation are not real for any value of k.

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In the first equation in the system of equations, y represents the money collected from selling sweatshirts. In the second equat

NeTakaya

Answer:

The solution x = 229.89 ≅ 230 (since we cannot have a decimal number of sweatshirts)implies that, the money collected from selling sweatshirts equals the money used in producing sweatshirts when 230 sweatshirts have been sold or produced.

Step-by-step explanation:

Here is the complete question

In the first equation in the system of equations, y represents the money collected from selling sweatshirts. in the second equation, y represents the money spent to produce x sweatshirts with team logos on them for a professional sports league.

y=35x; y=-0.05(x-400)²+9,492

what does the solution of the system represent in this context?

Solution

The solution of the system is obtained when both equations are equal. That is y=35x = y=-0.05(x-400)²+9,492 .

So, 35x = -0.05(x-400)² + 9,492.

Expanding the right side, we have

35x = -0.05(x² - 800x + 160000) + 9492

35x = -0.05x² -800x × -0.05 + (-0.05) × 160000 + 9492

35x = -0.05x² +40x - 8000 + 9492

35x = -0.05x² +40x + 1492

Collecting all the terms to the left side, we have

0.05x² - 40x - 1492 + 35x = 0

0.05x² - 5x -1492 = 0

Using the quadratic formula,

$x = \frac{-(-5) +/- \sqrt{(-5)^{2} - 4 X 0.05 X - 1492} }{2X0.05} = \frac{5 +/- \sqrt{25 + 298.4} }{0.1} = \frac{5 +/- \sqrt{323.4} }{0.1}\\= \frac{5 +/- 17.983 }{0.1}\\= \frac{5 - 17.983 }{0.1} or \frac{5 + 17.983 }{0.1}\\= \frac{-12.983 }{0.1} or \frac{22.983 }{0.1}\\= -129.83 or 229.83$

We choose the positive answer x = 229.83. Since we cannot have a decimal number of sweatshirts, we approximate to the nearest whole number. So, x = 229.83 ≅ 230 sweatshirts.

The solution implies that the money collected from selling sweatshirts equals the money used in producing sweatshirts when 230 sweatshirts have been sold or produced.

We confirm that by plugging in x = 229.83 in both equations.

y = 35x = 35(229.83) = 8044.05 ≅ 8044.1

y=-0.05(x-400)²+9,492 = y=-0.05(229.83-400)²+9,492 = y=-0.05(-170.17)²+9,492 = y=-0.05(28,957.8289)+9,492 = -1447.8914 + 9492 = 8044.11 ≅ 8044.1

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3 years ago

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2 years ago

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Three times the sum of a number and seven is 23 less than five times the number find the number wrong your answer to the nearest

mote1985 [20]

so you have your two equations 3x+7=5x-23 and solve for x which is your "number" leaving the answer to be x=15

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3 years ago

A carrot has

4vir4ik [10]

Answer:

B- For an equal number of servings, the bananas will have three times as much sugar

Step-by-step explanation:

The complete question is

A carrot has 5 grams of sugar per serving. A banana has 15 grams of sugar per serving. Which statement is true?

A- There will always be more sugar in 10 servings of carrots than in a smaller number of servings of bananas.

B- For an equal number of servings, the bananas will have three times as much sugar.

C- For an equal number of servings, the bananas will always have 10 more grams of sugar.

D- The amount of sugar in two servings of carrots is 30 grams.

Verify each statement

A- There will always be more sugar in 10 servings of carrots than in a smaller number of servings of bananas

The statement is False

Because

In 10 servings of carrots there are 10(5)=50 grams of sugar

In 5 servings of banana there are 5(15)=75 grams of sugar

therefore

50 g < 75 g

B- For an equal number of servings, the bananas will have three times as much sugar

The statement is true

Because

In one serving of carrots there are 5 grams of sugar

In one serving of bananas there are 15 grams of sugar

The ratio of grams of sugar in a serving of bananas to grams of sugar in a serving of carrots is 15:5

Simplify

3:1

therefore

An equal number of servings, the bananas will have three times as much sugar

C- For an equal number of servings, the bananas will always have 10 more grams of sugar.

The statement is False

Because

In 10 servings of carrots there are 10(5)=50 grams of sugar

In 10 servings of banana there are 10(15)=150 grams of sugar

$50+10\neq 150$

D- The amount of sugar in two servings of carrots is 30 grams

The statement is False

Because

In 2 servings of carrots there are 2(5)=10 grams of sugar

$10\neq 30$

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3 years ago

Prove that the roots of x2+(1-k)x+k-3=0 are real for all real values of k​

Prove that the roots of x2+(1-k)x+k-3=0 are real for all real values of k