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2 years ago

X is directly proportional to y. When x = 4, y = 7. Work out the value of y when x = 12

Mathematics

1 answer:

AysviL [449]2 years ago

6 0

Answer:

y = 21

Step-by-step explanation:

When x is directly proportional to y:

When x increases, y also increases.

In this case, it is so you write,

1. Write down the formula: y=kx

k being the constant.

Let's use "When x = 4, y = 7" to work out the constant.

2. Substitute the 'when' values: 7=k×4

3. Rearrange to find the constant: 7÷4=k

4. Find k: k=1.75

Now let's see the new problem, 'what is y when x = 12'.

5. Substitute the values now but keep the constant: y = 1.75 × 12

6. Rearrange if needed.

7. Find the missing value: y = 21

Hope this helped and if you require further assistance from me please comment below! :)

Ps: If it was inversely proportional then the formula would be y = k / x

with k still being the constant.

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Answer:

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Answer:

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Step-by-step explanation:

The equation of the tangent to the circle at (-6,8) is of the form:

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$m_{1}\times m_{2}=-1$

At any point on the circle, the normal line at a point is always perpendicular to the tangent line at that point.

Hence :

$m_{normal} \times m_{tangent}=-1$

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= ∞

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Putting m=0 in equation 1 we get:

c = 8

The equation of tangent line at (-6,8) is:

y = 8

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