Which equation is an identity? 3(x – 1) = x + 2(x + 1) + 1
x – 4(x + 1) = –3(x + 1) + 1
2x + 3 =1/2 (4x + 2) + 2
1/3(6x – 3) = 3(x + 1) – x – 2

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

If 1.4% of the mass of a human body is calcium, how many kilograms of calcium are there in a 165-pound man? 1.0 kg ca 5.1 kg ca 1.0 x 102 kg ca 5.1 x 102 kg ca

The hockey team has been great! in 2008 they won 20% more games than in 2007. in 2009 they won 50% more games than in 2008. what was their overall percentage increase from 2007 through 2009?