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3 years ago

7

Help please! this ones easy i just dont know how to do it

1 answer:

nikitadnepr [17]3 years ago

5 0

Is there a variable for i?

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The perimeter of a rectangle is 24 inches. Find the dimensions if it’s length is 3 inches greater than its width

Jlenok [28]

2l+2w=24
l=3+w
The first equation comes from the perimeter formula. Since it is a rectangle, there are two lengths and two widths, which must all be added to get the perimeter. The second equation shows that the length is equal to the width plus three. In order to solve this equation, the substitution method should be used, since the one equation is already set equal to one of the variables (L)

2l+2w=24
l=3+w

2(3+w)+2w=24
Use distributive property to get rid of the parentheses
2(3+w)+2w=24
2(3)+2(w)+2w=24
6+2w+2w=24
Simplify like terms on the left side of the equation
6+2w+2w=24
6+4w=24
Subtract six from each side so that all of the w's are on one side
6+4w-6=24-6
4w=18
Divide each side by four to find the value of one w
4w/4=18/4
w=4.5
Plug 4.5 into the one equation to find the value of l
l=3+4.5
l=7.5
Put the numbers into the first equation and simplify:
2(7.5)+2(4.5)=24
15+9=24
24=24
So the length would be 7.5 inches, and the width would be 4.5 inches

7 0

3 years ago

Multiply 2m+(-n) by -3m+(-5)

galben [10]

Answer:

2m+3mn-5

Step-by-step explanation:

2m+n x 3m + (-5)

2m +3mn + (-5)

2m +3mn -5

3 0

4 years ago

"You are dating Moon rocks based on their proportions of uranium-238 (half-life of about 4.5 billion years) and its ultimate dec

Olenka [21]

Step-by-step explanation:

a.

Initial mass of the isotope = x

Time taken by the sample to decay its mass by 41% = t

Formula used :

$N=N_o\times e^{-\lambda t}\\\\\lambda =\frac{0.693}{t_{\frac{1}{2}}}$

where,

$N_o$ = initial mass of isotope = x

N = mass of the parent isotope left after the time, (t) = 59% of x = 0.59x

$t_{\frac{1}{2}}$ = half life of the isotope = 4.5 billion years

$\lambda$ = rate constant

Now put all the given values in this formula, we get

$0.59x=x\times e^{-(\frac{0.693}{\text{4.5 billion years}})\times t}$

t = 3.4 billion years

The age a rock is 3.4 billion years.

b.

Initial mass of the isotope = x

Time taken by the sample to decay its mass by 35%= t

Formula used :

$N=N_o\times e^{-\lambda t}\\\\\lambda =\frac{0.693}{t_{\frac{1}{2}}}$

where,

$N_o$ = initial mass of isotope = x

N = mass of the parent isotope left after the time, (t) = 65% of x = 0.65x

$t_{\frac{1}{2}}$ = half life of the isotope = 4.5 billion years

$\lambda$ = rate constant

Now put all the given values in this formula, we get

$0.65x=x\times e^{-(\frac{0.693}{\text{4.5 billion years}})\times t}$

t = 2.8 billion years

The age a rock is 2.8 billion years.

5 0

4 years ago

In a basketball game, Ra’Shiek made 23 baskets. Each of the baskets was worth either 2 or 3 points, and Ra’Shiek scored a total

Reptile [31]

Answer:

Step-by-step explanation:

????

7 0

3 years ago

Your doctor prescribes you to take 400 milligrams of medicine every 8 hours. How many ounces of medicine do you take in a day?

Arturiano [62]

1200 milligrams. There are 24 hours in a day. 24/8 is 3. You multiply 400 by 3 and you get 1200

5 0

4 years ago

Read 2 more answers