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forsale [732]
3 years ago
7

A first number plus twice a second number is 24. twice the first number plus the second totals 21. find the numbers.

Mathematics
1 answer:
Ulleksa [173]3 years ago
4 0
We do like the following:
Set the first number is a and the second is b.
We have two equations: a+2xb=24, 2xa+b=21
And we have 2xa+4xb=48 or 2xa=48-4xb
So: 48-4xb+b=21 or -3xb=21-48=-27 and we got b=-27:(-3)=9 and a= 6
a=6 and b=9
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Converse of the Pythagorean theorem
jonny [76]
I only know how to do # 7.

7. 4.5^2 + 6^2 = 7.5^2
20.25 + 36 = 56.25
56.25 = 56.25

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7 0
3 years ago
Tell whether the given value is a solution of the inequality. (yes or no)<br><br> -2 ≤ k/3; k = -9
olga55 [171]

Answer:  No, it is not a solution

Work Shown:

-2 ≤ k/3

-2 ≤ -9/3

-2 ≤ -3

The last inequality is false because -3 should be smaller than -2 (not the other way around). Use a number line to help see this.

Since the last inequality is false, the original inequality must also be false for that particular k value. Therefore, k = -9 is not a solution.

4 0
2 years ago
Im still not sure, can someone help me?
viktelen [127]

Answer: 9 associate property 8 commutative property

Step-by-step explanation:

8 0
3 years ago
Pure copper was mixed with a 10% copper alloy to produce an alloy thát was 25% copper. How much of the pure copper and how much
lora16 [44]

Answer:

6kg pure copper and 30 kg 10% copper was mixed to give 36kg of 25% alloy

Step-by-step explanation:

Here, we want to produce 36 kg of 25% alloy

Let the Pure copper be x kg while 10% alloy be y kg

Pure copper is simply 100% copper

Thus;

x + y = 36 •••••(i)

Then;

100% of x + 10% of y = 25% of 36

= x + 0.1y = 9 •••••• ii)

From i x = 36-y

from ii, x = 9-0.1y

Equate both x

36-y = 9-0.1y

36-9 = 0.1y + y

0.9y = 27

y = 27/0.9

y = 30

x = 36-y

x = 36-30

x = 6 kg

8 0
3 years ago
Calculate the side lengths a and b to two decimal places.
Strike441 [17]

Answer:

A.)=24.78

B.)=26

C.)=7.33

D.)=25.44

Step-by-step explanation:

A.)11.40+13.38=24.78

B.)11+15=26

C.)4.18+3.15=7.33

D.)10.92+14.52=25.44

7 0
2 years ago
Read 2 more answers
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