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4 years ago

Write down the value of 2jk - 10j when j = 9 and k = 2 Write down only the number, nothing else

Mathematics

1 answer:

Georgia [21]4 years ago

8 0

Answer:

-54

Step-by-step explanation:

2jk - 10j

Let j = 9 and k=2

2*9*2 - 10 *9

36 - 90

-54

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Determine and prove what shape is formed for the given coordinates for ABCD, and then find the

ella [17]

Answer:

Square

Step-by-step explanation:

Plot points A (10,-4), B (6,-7), C (3,-3), D (7,0) on the coordinate plane.

Find slopes of the sides:

$AB:\ \dfrac{-7-(-4)}{6-10}=\dfrac{3}{4}\\ \\BC:\ \dfrac{-3-(-7)}{3-6}=-\dfrac{4}{3}\\ \\CD:\ \dfrac{0-(-3)}{7-3}=\dfrac{3}{4}\\ \\DA:\ \dfrac{-4-0}{10-7}=-\dfrac{4}{3}$

The slopes of opposite sides are the same, so opposite sides are parallel. The slopes of adjacent sides have product of -1, then adjacent sides are perpendicular.

Find the lengths of all sides:

$AB=\sqrt{(10-6)^2+(-4-(-7))^2}=\sqrt{4^2+3^2}=\sqrt{16+9}=\sqrt{25}=5\ units\\ \\BC=\sqrt{(6-3)^2+(-7-(-3))^2}=\sqrt{3^2+4^2}=\sqrt{16+9}=\sqrt{25}=5\ units\\ \\CD=\sqrt{(3-7)^2+(-3-0)^2}=\sqrt{4^2+3^2}=\sqrt{16+9}=\sqrt{25}=5\ units\\ \\AD=\sqrt{(10-7)^2+(-4-0)^2}=\sqrt{3^2+4^2}=\sqrt{16+9}=\sqrt{25}=5\ units\\ \\$

All four sides are of the same length.

Quadrilateral ABCD is a square (all sides of equal length and perpendicular)

4 0

3 years ago

Help will mark brainlist if it correct If each edge of a cube is increased by 2 inches, the

Anastasy [175]

Answer:

D. sum of these edges is increased by 24 inches -- True

Step-by-step explanation:

Given a cube and its edge is increased by 2 inches.

To study the effect of this increase in the Volume, area of each face, diagonal and sum of edges.

Solution:

Let the side of original cube = a inches.

Formula for volume of cube:

$V =side^3 = a^3$

If the side is increased by 2 inches, the side becomes (a+2) inches.

So, new volume, $V' = (a+2)^3$

Using the formula:

$(x+y)^3 =x^3+y^3+3xy(x+y)$

$V' = (a+2)^3 = a^3+8+3\times 2 \times a(a+2)=a^3+8+6a(a+2)$

So, $V' = V + 8+6a(a+2)$

Volume increased by 8+6a(a+2) [which is not equal to 8]

So, statement is false:

A. volume is increased by 8 cubic inches -- False

Each face in a cube is a square.

Area of each face, A = $side^2 = a^2$

New area, A' = $(a+2)^2$

Using the formula: $(x+y)^2 =x^2+y^2+2xy$

$A' = a^2+4+4a$

Area increased by 4+4a [which is not equal to 4 sq inches]

B. area of each face is increased by 4 square inches -- False

Diagonal of each face = $a\sqrt2$

Increase of 2 in the edge:

New diagonal = $(a+2)\sqrt2 = a\sqrt2+2\sqrt2$

So, increase of $2\sqrt2$ not 2.

C. diagonals of each face is increased by 2 inches -- False

There are 12 number of edges in a square.

So sum of all 12 edges = 12a

When edge is increased by 2, sum of all edges = 12(a+2) = 12a + <em>24</em>

An increase of 24.

D. sum of these edges is increased by 24 inches -- True

4 0

3 years ago

Prob the last two, but wtvvv.<br> HELP THOO

Dafna1 [17]

Answer:

Combine the ones to make 8 ones

Step-by-step explanation:

It seems the most reasonable. (Also, all the other options are wrong-) I just don't see why it's making you go through this process when you can just add 12 + 6 in your head lol.

3 0

3 years ago

Please help

trapecia [35]

Between emma and dave, we have 7/10ths of the money

3x + 2x = 7/10

5x = 7/10

x=(7/10)/5

x= 14/100

Dave will get 28/100 or 7/25ths

Check : 30/100 Colin
42/100 Emma
+ 28/100 Dave
-----------
100/00

7 0

3 years ago

Tim received 55 dollars for his birthday. He went to a sporting goods store and bought a baseball glove, baseball, and bat. He h

dexar [7]

Answer:

He had spent $35 on ⚾ gear

8 0

3 years ago