Skip to main content
Ch. 5 - Systems and Matrices
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 6, Problem 31

Solve each system of equations. State whether it is an inconsistent system or has infinitely many solutions. If a system has infinitely many solutions, write the solution set with x arbitrary.
9x - 5y = 1
-18x + 10y = 1

Verified step by step guidance
1
Start by writing down the system of equations clearly: \[9x - 5y = 1\] \[-18x + 10y = 1\]
Observe the coefficients of the variables in both equations. Notice that the second equation looks like it might be a multiple of the first. To check this, multiply the first equation by -2: \[-2 \times (9x - 5y) = -2 \times 1\] which gives \[-18x + 10y = -2\]
Compare the result from step 2 with the second equation in the system: The second equation is \[-18x + 10y = 1\], but after multiplying the first equation by -2, we got \[-18x + 10y = -2\]. Since the left sides are identical but the right sides are different, this means the two equations contradict each other.
Because the equations contradict, the system has no solution. This type of system is called an inconsistent system.
Therefore, conclude that the system is inconsistent and does not have any solutions.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Systems of Linear Equations

A system of linear equations consists of two or more linear equations with the same variables. The goal is to find values for the variables that satisfy all equations simultaneously. Solutions can be a single point, infinitely many points, or no solution.
Recommended video:
Guided course
4:27
Introduction to Systems of Linear Equations

Inconsistent and Dependent Systems

An inconsistent system has no solutions because the equations represent parallel lines that never intersect. A dependent system has infinitely many solutions because the equations represent the same line, meaning one equation is a multiple of the other.
Recommended video:
Guided course
6:57
Classifying Systems of Linear Equations

Solving Systems by Substitution or Elimination

Methods like substitution or elimination help solve systems by isolating variables or combining equations to eliminate variables. Elimination involves adding or subtracting equations to remove one variable, simplifying the system to find solutions or determine consistency.
Recommended video:
Guided course
5:48
Solving Systems of Equations - Substitution