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Dafna11 [192]
3 years ago
6

I think of a number double it add 15 my number is 21 what number was i thinking about

Mathematics
1 answer:
AleksandrR [38]3 years ago
5 0

Hello from MrBillDoesMath!

Answer:

3

Discussion:

Let the number be "n",

2n + 15  = 21          =>  subtract 15 from both sides

2n = 21 - 15 = 6     =>   divide both sides by 2

n = 6/2 = 3

Check: Start with 3. Double it (gives 6), add 15 to it ( 6 + 15)  which gives 21/

Thank you,

MrB

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Eleanor and Max used two rectangular pieces of plywood, placed end-to-end, to make a long rectangular stage for the school play.
Flauer [41]

Answer:the width of plywood = 6.25 feet wide or  6 1/4 feet wide

Step-by-step explanation:

Step 1

Area of  a rectangular plywood = length x width

Area of Ist Plywood= 7 x w

Area of 2nd  Plywood= 61/2 x w=6.5 xw

But Total Arae of trhe two Plywoods are = 84 3/8 square feet.

Therefore Our equation to solve the problem becomes

Area of Ist Plywood + Area of 2nd  Plywood =84 3/8 square feet.

7w + 6.5w =  84 3/8

13.5w= 84 3/8

w =  84 3/8/13.5

675/8  / 13.5

w=6.25

Therefore the width of plywood = 6.25 feet wide or 6 1/4 feet.

3 0
3 years ago
Is 0 14 closed under multiplication
Elden [556K]
No because 0x14 would be 0 BUT it is still multiplication.
4 0
3 years ago
(0.00032)(5.2x10^6)/6.4x10^5
Elena-2011 [213]

Answer:

26000000

Step-by-step explanation:

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7 0
3 years ago
The what value complete the square for the expression x squared plus 16x
Troyanec [42]
Take the coefficient of the x-term, half it, then square that. add this to both sides

x² + 16x. coefficient of x is 16. half of 16 is 8. 8²=64

x² + 16x + 64 =64. this is your answer but to continue

x² + 16x + 64 = 64
(x+8)² = 64
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6 0
3 years ago
Marcus solved a problem and found out that 190% of 20 is 380. Is he correct
avanturin [10]

Answer: He is Incorrect, It's 38

Work: For this question, I did the Cross-Product Method. The Cross Product Method is when you solve equation via to fractions. With the CPM, One one side of the fraction, I had x / 20 (Twenty being the whole number) and on the other side, I had 190/100 (190 being the percent) After setting this up, I made the equation. 190 times 20 is 3800, and the other multiplication is 100 times x which is 100x. So, the new equation is 3800 = 100x. I divided both sides by 100, and the answer is 38 = x

<em>I hope this helps, and Happy Holidays! :)</em>

8 0
3 years ago
Read 2 more answers
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