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3 years ago

What is the value of x?

Mathematics

2 answers:

Mazyrski [523]3 years ago

6 0

x/20 = 21/14 (similar proportions)

x/20 = 3/2 (simplify by canceling out a factor of 7)

x = 30

velikii [3]3 years ago

3 0

X= 30 and the jlk is divisible by 1.5 to get pqr

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Solve for x: 2x − 2 > 4x + 6. x < −4 x > −4 x < 4 x > 4

igomit [66]

Answer:

The answer is the first choice, x < −4.

Step-by-step explanation:

Let's solve your inequality step-by-step.

2x−2>4x+6

Step 1: Subtract 4x from both sides.

2x−2−4x>4x+6−4x

−2x−2>6

Step 2: Add 2 to both sides.

−2x−2+2>6+2

−2x>8

Step 3: Divide both sides by -2.

x<−4

3 0

3 years ago

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.

8 0

3 years ago

Read 2 more answers

3. The diameter of the large bird bath is 6 feet. The CGJ girls plan to put bird perches around the outside edge of the bath suc

Leokris [45]

First we need to determine the circumference of the bath.

Circumference = Diameter X pi

6(pi) = 18.84 feet

and the girls want to put perches that are at least 3 feet between each other so you can just divide the circumference by 3

18.84 / 3 = 6.28 so 6

If you don't understand the concept then think of it like this, if you have in total 18.84 feet and you want to place something down every 3 feet then start subtracting 3 from your total till you can't add anymore perches.

18 - 3 = 15
15 - 3 = 12
12 - 3 = 9
9 - 3 = 6
6 - 3 = 3
3 - 3 = 0

We subtracted 3, SIX times so we added 6 perches

7 0

3 years ago

4. (07.05 MC)

Papessa [141]

Answer:

xnone=

Step-by-step explanation:

5X+3x-15=6x+2x-15

8x-15=8x+15

-15=15

4 0

1 year ago

Question 10

Anna11 [10]

Answer:

6,000 dollars

Step-by-step explanation:

We first need to find out how much it would cost Danielle for a month if she chose the second option

200 + 40 = 240

240 x 30 = 7,200

Now that we know how much Danielle would pay if she chose the second option, now we need to find out how much she saved.

7,200 - 1,200 = 6,000

So Danielle saved 6,000 dollars by choosing the first option instead of the second one.

4 0

3 years ago