## advincula 2 years ago Y is directly proportional to X where Y=81 and X=9 Find Y if X=7 ..... i will wait for the answer . thanks :))

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1. akkib89

y=kx Putting Y=81 and X=9, we get, k=9 Now when x=7 y=7x9=63

2. akkib89

k=constant of proportionality

3. UnkleRhaukus

$y(x)\propto x$$y(x)=kx$ $y(9)=k\times9=81$$\qquad\qquad k=\frac{81}9$ $y(7)=k\times7=\frac{81}9\times7\color{grey}=$

4. jishan

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