Question 280666
The phrase "y varies directly as (something)" it means:
y = k*(something)
where k is some constant.
So your equation is:
{{{y = k*sqrt(x)}}}<br>
Now you<ol><li>use this equation and the given x,y pair (25, -15) to find out what k is.</li><li>rewrite the equation with the value you found for k.</li><li> use the new equation to find the x for y = -108.</li></ol>