Table of contents
- 0. Fundamental Concepts of Algebra3h 29m
- 1. Equations and Inequalities3h 27m
- 2. Graphs1h 43m
- 3. Functions & Graphs2h 17m
- 4. Polynomial Functions1h 54m
- 5. Rational Functions1h 23m
- 6. Exponential and Logarithmic Functions2h 28m
- 7. Measuring Angles40m
- 8. Trigonometric Functions on Right Triangles2h 5m
- 9. Unit Circle1h 19m
- 10. Graphing Trigonometric Functions1h 19m
- 11. Inverse Trigonometric Functions and Basic Trig Equations1h 41m
- 12. Trigonometric Identities 2h 34m
- 13. Non-Right Triangles1h 38m
- 14. Vectors2h 25m
- 15. Polar Equations2h 5m
- 16. Parametric Equations1h 6m
- 17. Graphing Complex Numbers1h 7m
- 18. Systems of Equations and Matrices3h 6m
- 19. Conic Sections2h 36m
- 20. Sequences, Series & Induction1h 15m
- 21. Combinatorics and Probability1h 45m
- 22. Limits & Continuity1h 49m
- 23. Intro to Derivatives & Area Under the Curve2h 9m
18. Systems of Equations and Matrices
Introduction to Matrices
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Solve the system of equations by using row operations to write a matrix in REDUCED row-echelon form.
4x+2y+3z=6
x+y+z=35x+y+2z=5
A
x=0,y=−3,z=4
B
x=−41,y=−419,z=211
C
x=1,y=4,z=−2
D
x=21,y=21,z=1

1
Step 1: Write the system of equations as an augmented matrix. The system is: 4x + 2y + 3z = 6, x + y + z = 3, 5x + y + 2z = 5. The augmented matrix is: [[4, 2, 3, 6], [1, 1, 1, 3], [5, 1, 2, 5]].
Step 2: Use row operations to get a leading 1 in the first row, first column. You can do this by swapping the first row with the second row, resulting in: [[1, 1, 1, 3], [4, 2, 3, 6], [5, 1, 2, 5]].
Step 3: Eliminate the first column below the leading 1 by using row operations. Subtract 4 times the first row from the second row, and 5 times the first row from the third row. This gives: [[1, 1, 1, 3], [0, -2, -1, -6], [0, -4, -3, -10]].
Step 4: Get a leading 1 in the second row, second column by dividing the second row by -2. The matrix becomes: [[1, 1, 1, 3], [0, 1, 0.5, 3], [0, -4, -3, -10]].
Step 5: Eliminate the second column below the leading 1 in the second row by adding 4 times the second row to the third row. This results in: [[1, 1, 1, 3], [0, 1, 0.5, 3], [0, 0, -1, 2]]. Now, back substitute to find the values of x, y, and z.
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