If y varies directly with x and y is 9 when x is 5, what is x when y is - 1

Question

Santino

Mathematics

7 June, 12:08

If y varies directly with x and y is 9 when x is 5, what is x when y is - 1

+4

Answers (2)

Know the Answer?

Izayah Weber · Answer 1

We use the fact that y = kx, where k is the constant of proportionality.

9 = 5k

9/5 = k

Now that we know k, we can find x when y = - 1.

-1 = x (9/5)

-1 / (9/5) = x

-5/9 = x

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Zachariah Fisher · Answer 2

x = - 0.56

Step-by-step explanation:

if y varies directly with x

i. e

y ∝ x

y = kx

where k is the constant of variation

when y is 9 and x is 5

9 = 5k

k = 9/5

k=1.8

when y=-1

then

-1=kx

-1=1.8x

x = - 0.56