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2 years ago

5

Find the "a" value so that the equation ax^2-10x + 25 = 0 has two equal, real roots.

1 answer:

alukav5142 [94]2 years ago

3 0

Answer:

Step-by-step explanation:

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You want to get from a point A on the straight shore of the beach to a buoy which is 54 meters out in the water from a point B o

anyanavicka [17]

Answer:

$x =\dfrac{45 \sqrt{6}}{ 2}$

Step-by-step explanation:

From the given information:

The diagrammatic interpretation of what the question is all about can be seen in the diagram attached below.

Now, let V(x) be the time needed for the runner to reach the buoy;

∴ We can say that,

$\mathtt{V(x) = \dfrac{70-x}{7}+\dfrac{\sqrt{54^2+x^2}}{5}}$

In order to estimate the point along the shore, x meters from B, the runner should stop running and start swimming if he want to reach the buoy in the least time possible, then we need to differentiate the function of V(x) and relate it to zero.

i.e

The differential of V(x) = V'(x) =0

= $\dfrac{d}{dx}\begin {bmatrix} \dfrac{70-x}{7} + \dfrac{\sqrt{54^2+x^2}}{5} \end {bmatrix}= 0$

$-\dfrac{1}{7}+ \dfrac{1}{5}\times \dfrac{x}{\sqrt{54^2+x^2}}=0$

$\dfrac{1}{5}\times \dfrac{x}{\sqrt{54^2+x^2}}= \dfrac{1}{7}$

$\dfrac{5x}{\sqrt{54^2+x^2}}= \dfrac{1}{7}$

$\dfrac{x}{\sqrt{54^2+x^2}}= \dfrac{1}{\dfrac{7}{5}}$

$\dfrac{x}{\sqrt{54^2+x^2}}= \dfrac{5}{7}$

squaring both sides; we get

$\dfrac{x^2}{54^2+x^2}= \dfrac{5^2}{7^2}$

$\dfrac{x^2}{54^2+x^2}= \dfrac{25}{49}$

By cross multiplying; we get

$49x^2 = 25(54^2+x^2)$

$49x^2 = 25 \times 54^2+ 25x^2$

$49x^2-25x^2 = 25 \times 54^2$

$24x^2 = 25 \times 54^2$

$x^2 = \dfrac{25 \times 54^2}{24}$

$x =\sqrt{ \dfrac{25 \times 54^2}{24}}$

$x =\dfrac{5 \times 54}{\sqrt{24}}$

$x =\dfrac{270}{\sqrt{4 \times 6}}$

$x =\dfrac{45 \times 6}{ 2 \sqrt{ 6}}$

$x =\dfrac{45 \sqrt{6}}{ 2}$

8 0

2 years ago

A 30% acid solution was mixed with a 10% acid solution. The result was 600g of a 15% solution. How much of each solution was use

AlexFokin [52]

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3 0

2 years ago

One package of socks cost $7. How many packages can you but with $56?

Akimi4 [234]

Step-by-step explanation:

$7 = 1 package socks

%56 = ??

$56/$7 × 1 package socks

= 8 × 1

= 8 package socks

Hope it helps!

4 0

2 years ago

What is the product of the 6th square number and the 5th square number?

lukranit [14]

Answer:

900.

Step-by-step explanation:

The first 6 square numbers are 1, 4, 9, 16, 25, 36,

The required product is 25 * 36

= 900.

8 0

2 years ago

If The diameter of a circle is 14 yards.what is the circles circumference

amm1812

Answer:

14π yards^2, or 43.98^2 yards rounded to 2dp

Step-by-step explanation:

circumference = diameter x π

6 0

2 years ago