Given:-
suppose y varies directly with x and y=-20 when x=-1.
To find:-
what direction variation equation relates to x and y what is the value of y when x=-10.
y varies directly with x that means y is directly propotional to x.
[tex]y=kx[/tex]Value of y=-20 when x=-1, so substituting we get,
[tex]\begin{gathered} -20=k\times-1 \\ 20=k \end{gathered}[/tex]So the value of k is 20.
So the direct equation is,
[tex]y=20x[/tex]Now we find the value of y when x=-10,
[tex]\begin{gathered} y=20\times-10 \\ y=-200 \end{gathered}[/tex]So the value of y is -200.
