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3 years ago

Simplify the following expression:

Mathematics

1 answer:

Keith_Richards [23]3 years ago

6 0

Answer:

Step-by-step explanation:

-2(2)-1+1(1)-1(-1)

Do multiplication

-4-1+1+1

Now add/subtract

-5+2

-3

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Katrina buys a 42-ft roll of fencing to make a rectangular play area for her dogs.

vekshin1

Answer:

(a) $l = -w + 21$

(b) Domain: $0$ (See attachment for graph)

Step-by-step explanation:

Given

$2(l + w) = 42$

$l = length$

$w = width$

Solving (a): A function; l in terms of w

All we need to do is make l the subject in $2(l + w) = 42$

Divide through by 2

$l + w = 21$

Subtract w from both sides

$l + w - w = 21 - w$

$l = 21 - w$

Reorder

$l = -w + 21$

Solving (b): The graph

In (a), we have:

$l = -w + 21$

Since l and w are the dimensions of the fence, they can't be less than 1

So, the domain of the function can be $0$

--------------------------------------------------------------------------------------------------

To check this

When $w = 1$

$l = -1 + 21$

$l = 20$

$(w,l) = (1,20)$

When $w = 20$

$l = -20 + 21$

$l = 1$

$(w,l)= (20,1)$

--------------------------------------------------------------------------------------------------

See attachment for graph

Solving (c): Write l as a function $f(w)$

In (a), we have:

$l = -w + 21$

Writing l as a function, we have:

$l = f(w)$

Substitute $f(w)$ for l in $l = -w + 21$

$l = -w + 21$ becomes

$f(w) = -w + 21$

5 0

2 years ago

Simplify this expression. 3^-3

Sphinxa [80]

Answer:

1/27 is the answer

Step-by-step explanation:

It is 1/(3^3) which is 1/27

4 0

2 years ago

please help me and explain. what is the value of <img src="https://tex.z-dn.net/?f=%20%5Cfrac%7Bx%7D%7By%7D%20" id="TexFormula1"

rosijanka [135]

$\frac{28}{x^2} = \frac{7}{xy}$
multiplying both sides by x^2
$28=\frac{7x^2}{xy}$
simplifying
$28= \frac{7x}{y}$
dividing by 7
$\frac{28}{7}= \frac{x}{y}$

8 0

2 years ago

What is the sale price 45% of 69.50

Zolol [24]

x 55
-------- = ---------
69.50 100

69.50*55= 3822.5
3822.5/100= 38.225
x=$38.22

5 0

2 years ago

In 2009 the life expectancy is about 80 life expectancy gains 5.7 years every decade. From 2009 in how many years would humanity

Dmitry [639]

Answer:

about 70 years

Step-by-step explanation:

Life expectancy (e) improves by 5.7 years every 10 years, so 5.7/10 = 0.57 years per year. For t years after 2009, it can be modeled by ...

e = 0.57t +80

We want to find when that is 120:

120 = 0.57t +80

40 = 0.57t

40/0.57 = t ≈ 70.2

About 70 years from 2009, humanity may achieve a life expectancy of 120 years.

3 0

2 years ago