Question 52837
1) Solve for r:
{{{I = E/R + r}}} Subtract {{{E/R}}} from both sides of the equation.
{{{I-(E/R) = r}}} or {{{r = I-(E/R)}}} This could also be written:
{{{I = (IR-E)/R}}}

2) Reduce to lowest terms:
{{{3/2y - 3/(2y+4)}}} A common denominator is {{{2y(2y+4)}}}
{{{(3(2y+4)-3(2y))/(2y(2y+4))}}} Simplifying this.
{{{(6y+12-6y)/(4y^2+8y)}}} Simplifying further.
{{{12/4(y^2+2y)}}} Cancel the 4's
{{{3/(y^2+2y)}}} or {{{3/y(y+2)}}}

3)Solve:
{{{x^(-3) = 8}}} Rewrite as:
{{{1/x^3 = 8}}} Multiply both sides by {{{x^3}}}
{{{1 = 8x^3}}} Divide both sides by 8.
{{{1/8 = x^3}}} Take the cube root of both sides.
{{{1/2 = x}}} or {{{x = 1/2}}}