True or False If an II x /I matrix A can be expressed as a product ofelementary matrices. then A is nonsingular.

Math 111: Chapter 1 Section 1 PRECALCULUS REVIEW The Real Number Line o Made up of the set of real numbers together with the addition, subtraction, multiplication and division o Each positive number lies to the right of the origin, Negative numbers to left of the origin o Coordinate: the real number that is associated with a point on the real number line Intervals o Open Interval: set of all real numbers that lie strictly between two fixed numbers a and b (a,b). Neither of its endpoints are included in the interval o Closed Interval: Both of its endpoints are included in the interval. o Half-Open Interval: Contain only one of their endpoints. [a,b) o Infinite Intervals: (-,), used for the set of all real numbers Exponents and Radicals: o Example: b n The base is b the superscript n is the Power 0 o b = 1 o If n is a positive integer, then the expression b 1/is the square root of b 1/n n (b ) = b o b p/= √b p –p/q p/q o b m =n1/ (m+n o a x a = a o a /a = a m-n m n m x n o (a ) n a n n o (ab) = a x b o (a/b) = (a /b )n o Rationalization: if a radical appears in the numerator or denominator, we the