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

Did you follow?

step-by-step explanation:

use pothagarean therom

a^2+b^2=c^2 so first ac

acm is a right triangle because c= 90°

and am (the hypotenuse or c) =16+9 =25

but there is not enough info we need another angle or side length