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Systems of Linear Equations

Systems of Linear Equations

1. Systems of Linear Equations: Algebra

Systems of Linear Equations: Algebra

2. Introduction

Introduction

3. Line, Plane, Space, Etc.

Line, Plane, Space, Etc.

4. Pictures of Solution Sets

Pictures of Solution Sets

5. Parametric Description of Solution Sets

Parametric Description of Solution Sets

6. Linear equations

Which of the following equations is linear in the unknowns x,y,zx,y,z?

7. Consistent or inconsistent?

How many solutions does the system

{x+2y=3x+2y=−3\left\{\begin{aligned} x + 2y &= 3 \\ x + 2y &= -3 \end{aligned}\right.

have?

8. Vocabulary: no solutions

In one word: a system of linear equations that has no solutions at all is called ______ .

9. How many parameters?

The plane x+y+z=1x + y + z = 1 in R3\mathbb{R}^3 has the parametric form (x,y,z)=(1−t−w, t, w)(x,y,z) = (1-t-w,\,t,\,w). How many parameters (free variables) does that description use? Enter a number.

10. Parametric form of a line

The two equations x+y+z=1x + y + z = 1 and x−z=0x - z = 0 describe a line in R3\mathbb{R}^3. Solve them using zz as the free variable, writing the line as (x,y,z)=(t, ?, t)(x,y,z) = (t,\ ?,\ t). Enter the yy-coordinate as an expression in tt (for example: 1-2t).

11. Solution counts

According to this section, which list gives all the possibilities for the number of solutions of a system of linear equations?

12. Solve a pair

Solve the system

{x+2y=52x−y=0\left\{\begin{aligned} x + 2y &= 5 \\ 2x - y &= 0 \end{aligned}\right.

and enter the solution as x,yx,y.

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