Jeff C. answered • 01/29/13

Music, Math, Public Speaking

It helps to think about what you would have to do to a number to find the number plus tax. The price of the stereo is the unknown variable (x).

x(1+r)=P Where r is the tax rate and P is the price of the item after tax.

x(1+.06)=429.30 Equation filled in

x(1.06)=429.30 Add the 1 and the tax rate

1.06x=429.30 Simplified

1.06x/1.06=429.30/1.06 Divide both sides by 1.06 to single out the variable

x=405 Variable discovered.

That is the complicated algebra fashion if you need it drawn out. Now to make it logically more simple just divide the end price by the (tax rate plus 1).

429.30/1.06 it will work every time.