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3 years ago

One meter of electrical cord costs 3 dollars. How much should one pay for 4 meters?? Please help me out here.

Mathematics

1 answer:

Snowcat [4.5K]3 years ago

3 0

Answer:

$12

Step-by-step explanation:

The best way to do this is with a simple ratio. If you pay $3 for one meter, then for 4 meters, you’d pay $12. You BOUGHT 4 times more cord, which means you’d PAY 4 times more. Thus, 3 x 4 = 12!

Or with ratios:

1 meter : $3

multiplying both sides by 4

4 meters : $12

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Evaluate 8(7x--3) when x=9

Schach [20]

I will assume that by "Evaluate 8(7x--3) when x=9" you meant:

"Evaluate 8(7x-3) when x=9."

First, substitute 9 for x in 7x-3: 7(9)-3 = 60. Rewrite the problem as:

8(60). Multiply. Answer: 480

5 0

3 years ago

PLEEASSEEEE Answer ASAP. Due in 5 Minutes. 25 points!!!!!!!!!

jonny [76]

Answer:

Here we will use the relationships:

$a^n*a^m = a^{n + m}$

$(a^n)^m = a^{n*m}$

$\frac{a^n}{a^m} = a^{n - m}$

And a number:

$a^n$

is between 0 and 1 if a is positive and larger than 1, and n is negative.

if a is positive and 0 < a < 1, then we need to have n positive such that:

0 < a^n < 1

A) $5^3*5^{-4} = 5^{3 + (-4)} = 5^{-1}$

This is between zero and 1,

B) $\frac{3^5}{3^{-6}} = 3^{5 - (-6)} = 3^{11}$

This is greater than 1, because the exponent is positive.

C) $(\frac{1}{4})^3*( \frac{1}{4})^2 = (\frac{1}{4})^{2 + 3} = (\frac{1}{4})^5$

Because a is smaller than 1, and the exponent is positive, then the expression is between 0 and 1.

D) $\frac{(-7)^5}{(-7)^7} = (-7)^{5 - 7} = -7^{-2}$

The exponent is negative (and pair) then the expression is between 0 and 1.

Remember that when the exponent is pair, we always have that:

(-N)^m = (N)^m

So (-7)^-2 = 7^-2

4 0

3 years ago

jenna's rectangular garden borders a wall. she buys 80 ft of fencing. what are the dimensions of the garden that will maximize i

FrozenT [24]

Answer:

The dimensions are x =20 and y=20 of the garden that will maximize its area is 400

Step-by-step explanation:

Step 1:-

let 'x' be the length and the 'y' be the width of the rectangle

given Jenna's buys 80ft of fencing of rectangle so the perimeter of the rectangle is 2(x +y) = 80

x + y =40

y = 40 -x

now the area of the rectangle A = length X width

A = x y

substitute 'y' value in above A = x (40 - x)

A = 40 x - x^2 .....(1)

Step :2

now differentiating equation (1) with respective to 'x'

$\frac{dA}{dx} = 40 -2x$ ........(2)

Find the dimensions

$\frac{dA}{dx} = 0$

40 - 2x =0

40 = 2x

x = 20

and y = 40 - x = 40 -20 =20

The dimensions are x =20 and y=20

length = 20 and breadth = 20

Step 3:-

we have to find maximum area

Again differentiating equation (2) with respective to 'x' we get

$\frac{d^2A}{dx^2} = -2$

Now the maximum area A = x y at x =20 and y=20

A = 20 X 20 = 400

Conclusion:-

The dimensions are x =20 and y=20 of the garden that will maximize its area is 400

verification:-

The perimeter = 2(x +y) =80

2(20 +20) =80

2(40) =80

80 =80

8 0

3 years ago

What is initial value for v(t)= 32000(0.90)^t and the value after 13 yrs

marusya05 [52]

He initial value is 32,000 and the value after 13 yrs is 8133.97

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3 years ago

Brielle and her family went to our diner. They got ice cream cone, a brownie, and a cookie. How much did they spend on dessert?

Svetlanka [38]

Answer:

$6.83

Step-by-step explanation:

A brownie costs $3.45, an ice cream costs $2.43, and a cookie costs $0.95. So $3.45 + $2.43 + $0.95 = $6.83. If you need to know the change if they paid with $10.00 also . . . That would be $10.00 - $6.83 = $3.17 change.

7 0

3 years ago