Exercise 3 Page 44

To solve for n, we need to isolate it by multiplying both sides of the equation by - 5. We should multiply because division and multiplication are inverse operations. We are allowed to do this by the Multiplication Property of Equality.

We will check our solution by substituting this result back into the original equation and simplifying. If doing so results in an identity, our solution is correct.

An identity occurs when the left-hand side and the right-hand side of an equation are equal to one another. Since substituting n=10 resulted in an identity, our solution is correct.