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3 years ago

Someone help me find the answer to this problem. 15a - 20 + 10a =

Mathematics

2 answers:

Oksi-84 [34.3K]3 years ago

7 0

Answer:

5a +20

Step-by-step explanation:

add or subtract the same variables

Alika [10]3 years ago

7 0

Answer:

25a-20

Step-by-step explanation:

Since there is no value after the equal sign, all you can do is combine like terms

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Jane wishes to bake an apple pie for dessert. The baking instructions say that she should bake the pie in an oven at a constant

Viktor [21]

Answer:

Therefore $k= \frac{ln2 }{18}$ , A=184

Step-by-step explanation:

Given function is

$T(t)=230 -e^{-kt}$

where T(t) is the temperature in °C and t is time in minute and A and k are constants.

She noticed that after 18 minutes the temperature of the pie is 138°C

Putting T(t) =138°C and t= 18 minutes

$138=230 -Ae^{-k\times 18}$

$\Rightarrow -Ae^{-18k}=138-230$

$\Rightarrow Ae^{-18k}=92$ .....(1)

Again after 36 minutes it is 184°C

Putting T(t) =184°C and t= 36 minutes

$184=230-Ae^{-k\times 36}$

$\Rightarrow Ae^{-36k}=230-184$

$\Rightarrow Ae^{-36k}=46$ .......(2)

Dividing (2) by (1)

$\frac{Ae^{-36k}}{Ae^{-18k}}=\frac{46}{92}$

$\Rightarrow e^{-18k}=\frac{46}{92}$

Taking ln both sides

$ln e^{-18k}=ln\frac{46}{92}$

$\Rightarrow -18k =ln (\frac12)$

$\Rightarrow -18k= ln1-ln2$

$\Rightarrow k= \frac{ln2 }{18}$

Putting the value k in equation (1)

$Ae^{-18\frac{ln2}{18}}=92$

$\Rightarrow A e^{ln2^{-1}}=92$

$\Rightarrow A.2^{-1}=92$

$\Rightarrow \frac{A}{2}=92$

$\Rightarrow A= 92 \times 2$

⇒A= 184.

Therefore $k= \frac{ln2 }{18}$ , A=184

7 0

3 years ago

At a restaurant, when a customer buys 4 pretzels , the fifth pretzel is free. Soft pretzels cost $3.90 each. You order 12 soft p

lesya692 [45]

Answer: ($3.90)(12) - (2)($3.90) = 39.00

39.00/12 = 3.25 per pretzel

5 0

3 years ago

On a coordinate plane, what is the difference between (-2,7) and (-2,-6)?

Shtirlitz [24]

If you mean distance, then we can use the distance formula to find out.

(x - x)² + (y - y)² = d² Distance formula
(-2 + 2)² + (7 + 6)² = d² Substitute the points; remember that when you subtract a negative, you add, and also remember to always subtract in the same direction (with the points (1,2) and (3,4), if you do 1 - 3, then do 2 - 4 and not 4 - 2)
(0)² + (13)² = d² Add
0 + 169 = d² Square
169 = d² Add
13 = d Take the square root of both sides to cancel out the exponent

The distance between (-2,7) and (-2,-6) is 13 units.

Hope this helps!

4 0

3 years ago

Find the total fare with 15% tip: 1 passenger, 512 miles.

Darina [25.2K]

Answer:

37.92

Step-by-step explanation:

just add

6 0

2 years ago

Read 2 more answers

Mary had to guess at a chosen number between 1 and 10, to get to be the first in line. What’s the probability that she’ll choose