1. 2.1 Solving Systems of Equations
Objectives: Solve systems of equations graphically and algebraically.

2. A set of two or more equations.
Systems of Equations:
A set of two or more equations.
Solution:
The intersection of the graphs
Ex. 1)
Solve the system of equations by graphing.
y = 4x – 18
y = ¾x - 5

3. Consistent:
A system of equations that has at least one solution.
Inconsistent:
A system of equations that has no solutions. (parallel lines)
Independent:
A system of equations that has exactly one solution.
Dependent:
A system of equations that has
infinitely many solutions. (same
lines…coincide)

4. See page 68 Elimination & Substitution:
Algebraic methods to solve a system of equations.
Ex. 2)
Use elimination to solve: 5x + 2y = 340
3x – 4y = 360
Ex. 3)
Use substitution to solve: y = 3x - 8
2x + y = 22

5. Ex. 4.)
The Cotton Club, a manufacturer of sweatshirts, has fixed costs of $2000 and a variable cost of $5.00 per sweatshirt. It sells sweatshirts for $15.00 each. a.) Find the break-even point. b.) What is the least number of sweatshirts the Cotton Club must sell to make a profit?