Question 1199169
If y is inversely proportional to the cube of x, what percent does y change if x decreases by by 25%?
<pre>{{{matrix(1,3, y, "=", k/x^3)}}} ----- y inversely proportional to cube of x
{{{matrix(1,3, y[2], "=", k/(.75^3x))}}} ----- Substituting .75 for x, since after a 25% reduction, 75% (.75) remains 

Comparing y and y<sub>2</sub>, we see a CHANGE from {{{matrix(1,3, 1/1, to, 1/.75^3)}}}
Therefore, <font color = red><font size = 4><b>change in y after 25% reduction in x</font></font></b> = {{{highlight_green(matrix(1,9, (1/(.75^3)  -  1)/1, "=", 1/(.75^3)  -  1, "=", 1.37037, "=", 1.37, for, highlight(matrix(1,3, a, "137%", INCREASE)))))}}}</pre>