Question

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

Answer 1

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

Answer 2

k=constant of proportionality

Answer 3

\[y(x)\propto x\]\[y(x)=kx\]
\[y(9)=k\times9=81\]\[\qquad\qquad k=\frac{81}9\]

\[y(7)=k\times7=\frac{81}9\times7\color{grey}=\]