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Solving a System by Elimination In Exercises \(13-30\) , solve the system by the method of elimination and check any solutions algebraically. $$ \left\\{\begin{array}{l}{4 b+3 m=3} \\ {3 b+11 m=13}\end{array}\right. $$

Short Answer

Expert verified
The solution to the system of equations is \(b = -0.12, m = 1.23\).

Step by step solution

01

Choose the Variable to Eliminate

Examine both of the equations and identify the variable which is easiest to eliminate. In this case, it is easier to eliminate \(b\) in both equations. This can be done by multiplying the first equation by 3 and the second equation by 4.
02

Modify the Equations

Multiply the first equation by 3 to result in \(12b + 9m = 9\), and multiply the second equation by 4 to obtain \(12b + 44m = 52\). This means, the two modified equations are: \[ \left\{ \begin{array}{l} {12b + 9m = 9} \ {12b + 44m = 52} \end{array} \right.\]
03

Eliminate the Variable \(b\)

Subtract the first modified equation from the second to eliminate \(b\). The result is \(35m = 43\). Then solve this: \( m = 43/35 = 1.23 \)
04

Substitute \(m\)

Substitute the value of \(m\) into one of the original equations, like, \(4b + 3(1.23) = 3\) or \(3b + 11(1.23) = 13\). Solving this, you get \(b = -0.12\)
05

Check the Solution

Substitute the values of \(m\) and \(b\) into both of the original equations to verify if those are correct solutions or not.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Elimination Method in Algebra
The elimination method, often utilized in algebra, is a systematic way of solving systems of linear equations. This method is particularly powerful as it can handle situations when substitution might be not as clearly straightforward or when graphing such equations is not feasible.

The main idea is to create a new equation where one of the variables is eliminated—this is accomplished by adding or subtracting the two equations after having multiplied one or both of them by a number that will equalize the coefficients of one of the variables. For the exercise in question, we aim to eliminate the variable 'b'. By choosing this variable, which appears to have relatively simple coefficients within the system, the goal of reduction is more readily achieved.

When applying the elimination method, it is critical to perform operations that maintain the equality of the equations. The given example demonstrates a sequence of multiplication steps, aligning the coefficients so that subtraction effectively eliminates 'b', paving the way for isolating 'm' and subsequently finding its value. This methodical progression exemplifies algebraic rigor and strategic problem-solving.
Algebraic Solutions Verification
After obtaining potential solutions for a system of equations, it is essential to verify that these solutions are indeed correct. There are multiple ways to perform this verification, with substitution being the most common one. In our solved exercise, the values of 'm' and 'b' were first calculated and then substituted back into the original equations to validate the solution.

To ensure that the substitution is accurate, you must substitute the found value of the variables into both equations individually. If each equation is satisfied by these values, meaning the left-hand side equals the right-hand side after substitution, then the solution is verified. If the substitution does not hold true for the original system, it indicates an error in the calculation process requiring revisiting and correcting the previous steps.

In essence, verification is an integral part of solving systems of equations, serving as a proof check of the algebraic manipulations and logic applied. It instills confidence in the solution and guards against the propagation of calculation or conceptual errors.
Substitution Method
The substitution method is another fundamental technique to solve systems of equations aside from the elimination method mentioned earlier. This approach involves isolating one variable in one of the equations and then substituting its expression into the other equation to solve for the second variable.

In practice, if the exercise had asked to solve the system using substitution, one possible approach might have been to solve the first equation for 'b', thus obtaining: \( b = \frac{3 - 3m}{4} \), and then replace 'b' in the second equation with this expression to find 'm'. After finding 'm', replace it in the expression for 'b', thus solving for 'b'.

The substitution method is particularly useful when the coefficients of one of the variables in either equation allow for easy isolation of the variable or when dealing with equations that do not lend themselves to convenient elimination. As a general problem-solving strategy, it's crucial to recognize which method—substitution or elimination—will be the most efficient and straightforward given the system of equations at hand.

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