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1 year ago

Why do we use variables in math?

Mathematics

2 answers:

Phoenix [80]1 year ago

8 0

Answer:

We use it to substitute an unknown number. We have a variable for a number we don’t know and as we solve the problem we can find the answer for the variable or unknown number.

Step-by-step explanation:

I hope it helps! Have a great day!
Anygays-

Westkost [7]1 year ago

7 0

Answer:

They are used for a number we don't know what is exactly. As we solve the problem, we learn what the number could be, but when we don't know a certain number or have to solve for the unknown number, we use a variable to substitute for it.

Step-by-step explanation:

I hope it helps! Have a great day!

Pan~

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Segment AB has endpoints at −2 and 12. What is the coordinate of its midpoint?

charle [14.2K]

Hi there!

$\large\boxed{5}$

Find the midpoint using the midpoint formula:

m = (p1 + p2) / 2

m = (-2 + 12) / 2

m = 10 / 2

m = 5.

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

A rectangle is 2 meters wide and 6 times as long as it is wide. Find the area and perimeter

Anna [14]

<u>PERIMETER</u>

Answer:

Answer is 28 m

Step-by-step explanation:

Breadth= 2m

Length= 2X6m

= 12m

Perimeter of a rectangle = 2X (Length+ Breadth)

= 2X (2+12)

= 2X14

= 28m

<u>AREA</u>

Answer:

Answer is 24 m

Explanation:

Length= 12

Breadth= 2

Area of a rectangle= Length X Breadth

= 12X2

= 24 sq. m

Hope it helps ;)

Please mark as brainliest!

4 0

2 years ago

16. A necklace of former First Lady Jacqueline Kennedy Onassis was originally worth $700. Its

marusya05 [52]

Answer:

30,114.3%

Step-by-step explanation:

Use the percent increase formula:

((new value - initial value) / initial value) x 100

Plug in the values:

((211,500 - 700) / 700) x 100

(210,800 / 700) x 100

= 30,114.29

So, the percent increase is 30,114.3%

6 0

3 years ago

Read 2 more answers

Evaluate 3x-2y; if x=7 and y=3

Zarrin [17]

Answer:

Step-by-step explanation:

3x - 2y = ?

3(7) - 2(3) = ?

21 - 6 = ?

= 15

All you have to do is substitute the given values & follow the order of operations! Best of luck.

3 0

3 years ago