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svetlana [45]
3 years ago
9

If x^2+25y^2=416 and x-5y=-16 the value of xy is a)16 b)8 c)-8 d)-16

Mathematics
1 answer:
pshichka [43]3 years ago
3 0

Answer:

(a)

Step-by-step explanation:

Note the expansion of (x - 5y)² is

(x - 5y)² = x² - 10xy + 25y² , that is

(x - 5y)² = x² + 25y² - 10xy ← substitute given values

(- 16)² = 416 - 10xy

256 = 416 - 10xy ( subtract 416 from both sides )

- 160 = - 10xy ( divide both sides by - 10 )

xy = 16 → (a)

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Answer:

31,564

Step-by-step explanation:

82,062 - 50,498 = 31,564

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3 years ago
Solve the equation.<br><br> 3(n+4)=12(6n+4)
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Answer:

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Step-by-step explanation:

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Which value is equivalent to (7x5x2/7x3)^2 x (5^0/2^-3)^3 x2^-9?
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Answer:

100/9

Step-by-step explanation:

(7*5*2/7*3)² * (5^0/2^-3)³ * 2^-9

Solution:

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Now cancel out 2 by 2

= (7*5*2/7*3)² * (1/1^-3)³ * 1^-9

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7 0
3 years ago
Cmonnnnnnnnnnnnnnnnnnnnnnn
Rufina [12.5K]

Answer:

75

Step-by-step explanation:

Area of a triangle is <em>l </em>x <em>w </em>(length x width)

That's 4 cm x 12 cm. Now you could go ahead and figure it out from there, but you have to remember it wants the answer in meters. It tells us that for every 4cm, it is 5m. The easiest way to figure this out is to convert to meters before multiplying. Since 4 cm is 5m, the <em>l </em>becomes 5m. 4 goes into 12 three times. So we would do 5 x 3 to get 15m for the new <em>w. </em>Now we can solve for area.

<em>l </em>x <em>w </em>= A

5m x 15m = A

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I hope this helped :)

8 0
3 years ago
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The correct answer is 36 degrees



good luck
5 0
3 years ago
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