Question

The value of y varies directly with x. if y=80 when x is 16, what is y when x is 80? I will give a medal. Please help solve with me.

Answer 1

\(\bf \begin{array}{cccllll}
\textit{something }&\textit{varies directly to }&\textit{something else}\\ \quad \\
\textit{something }&={\color{red}{ \textit{some value }}}&\textit{something else}\\ \quad \\
y&={\color{red}{ n}}&x&\implies y={\color{red}{ n}}x
\end{array}\\ \quad \\
y=80\qquad x=16\qquad y={\color{red}{ n}}x\implies 80={\color{red}{ n}}\cdot 16\)

solve for "n", or the "constant of variation"
then plug it back in the equation

to know what "y" is when x = 80
just set in the equation x to 80 :)

Answer 2

5*16=80

Answer 3

well... you mean n = 5
yes so that means the equation is
y = 5x

what's "y" if x = 80?
well

\(\bf y=5x\qquad x=80\implies y=5\cdot 80\)

Answer 4

y=400

Answer 5

yeap
since n=5 \(\bf y=80\qquad x=16\qquad y={\color{red}{ n}}x\implies 80={\color{red}{ n}}\cdot 16\implies \cfrac{\cancel{ 80}}{\cancel{ 16}}=n=5\)

thus y = 5x

Answer 6

Thanks, thats the final answer right?

Answer 7

yeap

Answer 8

yw