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3 years ago

F(x) = -3x – 2 g(x) = 2x + 5 Find (f*g)(5)

Mathematics

1 answer:

antiseptic1488 [7]3 years ago

3 0

Answer:

hope it will help u in understanding

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In a right triangle ABC, CD is an altitude, such that AD=BC. Find AC, if AB=3 cm, and CD= 2 cm.

konstantin123 [22]

Consider right triangle ΔABC with legs AC and BC and hypotenuse AB. Draw the altitude CD.

1. Theorem: The length of each leg of a right triangle is the geometric mean of the length of the hypotenuse and the length of the segment of the hypotenuse adjacent to that leg.

According to this theorem,

$BC^2=BD\cdot AB.$

Let BC=x cm, then AD=BC=x cm and BD=AB-AD=3-x cm. Then

$x^2=(3-x)\cdot 3,\\ \\x^2=9-3x,\\ \\x^2+3x-9=0,\\ \\D=3^2-4\cdot (-9)=9+36=45,\\ \\\sqrt{D}=\sqrt{45}=3\sqrt{5},\\ \\x_1=\dfrac{-3-3\sqrt{5} }{2}0.$

Take positive value x. You get

$AD=BC=\dfrac{-3+3\sqrt{5} }{2}\ cm.$

2. According to the previous theorem,

$AC^2=AD\cdot AB.$

Then

$AC^2=\dfrac{-3+3\sqrt{5} }{2}\cdot 3=\dfrac{-9+9\sqrt{5} }{2},\\ \\AC=\sqrt{\dfrac{-9+9\sqrt{5} }{2}}\ cm.$

Answer: $AC=\sqrt{\dfrac{-9+9\sqrt{5} }{2}}\ cm.$

This solution doesn't need CD=2 cm. Note that if AB=3cm and CD=2cm, then

$CD^2=AD\cdot DB,\\ \\2^2=AD\cdot (3-AD),\\ \\AD^2-3AD+4=0,\\ \\D$

This means that you cannot find solutions of this equation. Then CD≠2 cm.

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3 years ago

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What is the equation of the line that passes through the point (6, 3) and has a slope of -2?

tekilochka [14]

We know the equation of a line is y=mx+b. We know the slope (m) is -2 and all we need is the intercept (b).

Since we know one point, we can plug in 6 for x and 3 for y (along with -2 for m) in our equation and then solve for b.

3= -2*6 + b

3= -12 + b

15 = b

Since we now know the intercept we can now write our equation:

y= -2x + 15

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3 years ago

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21 people are over 15

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2 years ago

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Money that is collecting interest in a bank account doubles in value every 10 years.

MArishka [77]

C . 2 to the power of 9

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2 years ago

Y=2 Enter the solution (x, y) to the system of equations shown 7y+3x=5

AnnyKZ [126]

Answer:

(x, y) = (-3, 2)

Step-by-step explanation:

Put the given value of y into the equation and solve for x.

... 7·2 +3x = 5

... 3x = -9 . . . . . . subtract 14

... x = -3 . . . . . . . divide by the x-coefficient

The solution (x, y) is (-3, 2).

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