Exercise 35 Page 9

To solve the given equation for a, we need to isolate it by adding 0.4 to both sides of the equation. We want to add 0.4 because subtraction and addition are inverse operations — they cancel each other out. This is allowed by the Addition 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.

Since substituting a=5.6 resulted in an identity, our solution is correct.