380 likes | 609 Views
7.1. Solving Systems of Two Equations. What you’ll learn about. The Method of Substitution Solving Systems Graphically The Method of Elimination Applications … and why Many applications in business and science can be modeled using systems of equations. Solution of a System.
E N D
7.1 Solving Systems of Two Equations
What you’ll learn about • The Method of Substitution • Solving Systems Graphically • The Method of Elimination • Applications … and why Many applications in business and science can be modeled using systems of equations.
Solution of a System A solution of a system of two equations in two variables is an ordered pair of real numbers that is a solution of each equation. A system is solved when all of its solutions are found.
Example Solving Word Problems with Systems Find the dimensions of a rectangular cornfield with a perimeter of 220 yd and an area of 3000 yd2.
Homework • Homework Assignment #9 • Read Section 7.2 • Page 575, Exercises: 1 – 65 (EOO)
7.2 Matrix Algebra
What you’ll learn about • Matrices • Matrix Addition and Subtraction • Matrix Multiplication • Identity and Inverse Matrices • Determinant of a Square Matrix • Applications … and why Matrix algebra provides a powerful technique to manipulate large data sets and solve the related problems that are modeled by the matrices.
Matrix Vocabulary Each element, or entry, aij, of the matrix uses double subscript notation. The row subscript is the first subscript i, and the column subscript is j. The element aij is in the ith row and the jth column. In general, the orderof anm × n matrix is m×n.
Inverses of n× n Matrices An n× n matrix A has an inverse if and only if det A≠ 0.
Properties of Matrices Let A, B, and C be matrices whose orders are such that the following sums, differences, and products are defined. 1. Community property Addition: A + B = B + A Multiplication: Does not hold in general 2. Associative property Addition: (A + B) + C = A + (B + C) Multiplication: (AB)C = A(BC) 3. Identity property Addition: A + 0 = A Multiplication: A·In = In·A = A 4. Inverse property Addition: A + (-A) = 0 Multiplication: AA-1 = A-1A = In |A|≠0 5. Distributive property Multiplication over addition: A(B + C) = AB + AC (A + B)C = AC + BC Multiplication over subtraction: A(B - C) = AB - AC (A - B)C = AC - BC