Checking Solutions to Equations Examples Page 1

Consider the equation (x - 9)² = x - 7. Is x = 11 a solution to this equation?

First evaluate the left-hand side expression for x = 11:

(11 - 9)² = (2)² = 4

Then evaluate the right-hand side expression for x = 11:

11 - 7 = 4

Because the left-hand and right-hand expressions match (evaluate to the same number) for x = 11, 11 is a solution to the equation (x - 9)² = x - 7. We can hang onto this one, and don't need to recycle it. Which is a shame, because we could have gotten 10 cents for it down at the grocery store.