So when Helmholtz recognized that thought moves at a finite rate, faster than a bird but slower than sound, he missed a fundamental difference between the brain and a telegraph. In our heads, speed is not always the most important thing. Sometimes what really matters is timing.
A solution of a quadratic equation is a value of the variable that makes the equation true. Many quadratic equations. can be solved by factoring and using the zero-factor property. The Zero-Factor Property: When the product of two real numbers is 0, at least one of them is 0.
factor(x, exclude = NULL) applied to a factor without NAs is a no-operation unless there are unused levels: in that case, a factor with the reduced level set is returned.