Question 480822
equation is:
84,000 = 2*x + 400
we're dealing in millions of liters.
subtract 400 from both sides of this equation to get:
83,600 = 2*x
divide both sides of this equation to get:
41,800 = x
41,800 million liters of water were saved in 2006.
this year, you saved 400 million liters more than 2 times that amount.
that means that this year you saved 2 * (41,800) + 400 = 83,600 + 400 = 84,000 million liters of water.