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kvasek [131]
3 years ago
10

Solve the system of linear equations by substitution x-y=-4 2x+y=4

Mathematics
1 answer:
mylen [45]3 years ago
3 0

Answer:

Given:

x-y=-4

2x+y=4

Step-by-step explanation:

x-y=-4

2x+y=4

add both the equation, we get

⇒  x-y=-4

  2x+y=4

⇒3x=-4+4

⇒3x=0

⇒x=0

∴ to find the value of y, put the value of x in any one equation

⇒x-y=-4

⇒0-y=-4

⇒-y=-4

⇒y=4

∴ x=0, y=4

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If 3x^2 + y^2 = 7 then evaluate d^2y/dx^2 when x = 1 and y = 2. Round your answer to 2 decimal places. Use the hyphen symbol, -,
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Solving for the first derivative, we have

\dfrac{\mathrm dy}{\mathrm dx}=-\dfrac{3x}y

Differentiating again gives

\dfrac{\mathrm d}{\mathrm dx}\bigg[6x+2y\dfrac{\mathrm dy}{\mathrm dx}\bigg]=\dfrac{\mathrm d}{\mathrm dx}\bigg[0\bigg]\implies 6+2\left(\dfrac{\mathrm dy}{\mathrm dx}\right)^2+2y\dfrac{\mathrm d^2y}{\mathrm dx^2}=0

Solving for the second derivative, we have

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3 years ago
Suppose that y varies inversely with x.Write an equation for the inverse variation Y=4 when x=7
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Answer:

If y varies inversely as x, then we write it as:

y = k/x


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k = 7*4 = 28


Put this back into our original equation to get:

y = 28/x



4 0
2 years ago
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