Question

Suppose y varies directly as x. If y = 12 when x = 4:
Write the general variation equation
Find the constant of variation, k.
Write a variation equation relating x and y using the value of k found in b).
Find y when x = -5.
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Answer 1

Answer:

y = -15

Step-by-step explanation:

Given that,

y varies directly as x i.e.

$y\propto x\\\\y=kx$

Where

k is the constant of variation.

Put y = 12 and x = 4 to find k.

$k=\dfrac{y}{x}\\\\k=\dfrac{12}{4}\\\\k=3$

Now put k = 3 and x = -5 and finding the value of y.

$y=3\times -5\\\\y=-15$

So, the value of y is equal to -15.