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3 years ago

Which equations are true?

Mathematics

2 answers:

Nutka1998 [239]3 years ago

6 0

B, the rest are wrong

aleksklad [387]3 years ago

4 0

Answer:

<h2>C : None of the above</h2>

Step-by-step explanation:

A : -2+(-2) = 0 False

-2+(-2) = -4

A negative plus a negative is actually a negative. When adding signed numbers, it is useful to think of positive numbers as gains and negative numbers as losses.

B : 2-(-2) = 0 False

2-(-2) = 4

Because there is subtraction sign so if subtraction sign added to negative sign it makes positive from 2-(-2) it will be 2+2

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1.Arsenic-74 is used to locate brain tumors. It has a half-life of 17.5 days. 90 mg wereused in a procedure. Write an equation t

Sophie [7]

$1)\text{ }N_t\text{ = 90\lparen}\frac{1}{2})^{\frac{t}{17.5}}$

2) 5.625 mg will be left

Explanation:

1) Half-life = 17.5 days

initial amount of Arsenic-74 = 90 mg

To get the equation, we will use the equation of half-life:

$\begin{gathered} N_t\text{ = N}_0(\frac{1}{2})^{\frac{t}{t_{\frac{1}{2}}}} \\ where\text{ N}_t\text{ = amount remaining} \\ N_0\text{ = initial amount} \\ t_{\frac{1}{2}\text{ }}\text{ = half-life} \end{gathered}$ $N_t\text{ = 90\lparen}\frac{1}{2})^{\frac{t}{17.5}}$

2) we need to find the remaining amount of Arsenic-74 after 70 days

t = 70

$\begin{gathered} N_t=\text{ 90\lparen}\frac{1}{2})^{\frac{70}{17.5}} \\ N_t\text{ = 5.625 mg} \end{gathered}$

So after 70 days, 5.625 mg will be left

4 0

1 year ago

Wiley wants to make as many snack

Ghella [55]

Answer:

Wiley can make 10 snack packs.

Step-by-step explanation:

Assuming that you can't put a fraction of one item in a snack pack and yoou must use all the items, Each pack must contain a integer number of items. The smallest possible way is for each snack pack to contain 3 slices of cheese and 4 crackers. This results in a total of 10 snack packs.

6 0

3 years ago

The expression on the left side of an equation is shown below.

Katyanochek1 [597]

Answer:its c i think

Step-by-step explanation:

7 0

3 years ago

I need help again... 4x divided by 8 = 3

iogann1982 [59]

X=6.0000000000000000000

3 0

3 years ago

Read 2 more answers

In a right triangle PQR,∠Q=90

Nikitich [7]

Answer:

a) PR = 17 cm, b) QR = 6 cm

Step-by-step explanation:

∠Q=90, so PQ and QR are legs, and PR is hypotenuse.

Pythagorean theorem PQ² + QR² = PR²

a) PQ² + QR² = PR²

8² + 15² = PR²

PR² = 289

PR = 17 cm

b) PQ² + QR² = PR²

8² + QR² = 10²

64 + QR² = 100

QR² = 36

QR = 6 cm

6 0

3 years ago