The algebraic expression describes
population of the United States (in millions) x years after 1960.
According to this model, when will the population reach 300
When we use the "=" symbol we are working with an equation. We can think of an
equation like a balance where both sides must be equal. We can add the same
both sides and keep the equation balanced. We can divide both sides by the same
(except zero) and keep the equation balanced. Our goal is to isolate, or "solve"
When solving linear equations, we are guaranteed that the
solution to our final equation is
exactly the same as the solution to the original equation when we add, subtract,
or divide both sides by the same number (except zero).
solve for x
5x = -20
divide both sides by 5 to undo multiplying x by 5
5x / 5 = -20 / 5
x = -4