Chapter 9: Problem 3
Determine whether \(x=-7, y=5,\) and \(z=\frac{3}{4}\) is a solution to the following systems: a. ? \(x-3 y+4 z=-19\) ? \(x-8 z=-13\) ? \(x+2 y=3\) b. ? \(3 x-2 y+16 z=-19\) ? \(3 x-2 y=-23\) ? \(8 x-y+4 z=-58\)
Short Answer
Expert verified
Point a is valid; point b is not a solution (second equation fails).
Step by step solution
01
Substitute into the First Equation of System a
Substitute the given values \(x = -7\), \(y = 5\), and \(z = \frac{3}{4}\) into the first equation of system a: \(x - 3y + 4z = -19\). Do the math: \(-7 - 3(5) + 4(\frac{3}{4}) = -7 - 15 + 3 = -19\). The equation holds true.
02
Check the Second Equation of System a
Now, substitute the same values into the second equation of system a: \(x - 8z = -13\). Calculate: \(-7 - 8(\frac{3}{4}) = -7 - 6 = -13\). This equation also holds true.
03
Verify the Third Equation of System a
Finally, substitute the values into the third equation: \(x + 2y = 3\). Check the result: \(-7 + 2(5) = -7 + 10 = 3\). This equation is correct as well.
04
Substitute into the First Equation of System b
Substitute the values into the first equation of system b: \(3x - 2y + 16z = -19\). Calculate: \(3(-7) - 2(5) + 16(\frac{3}{4}) = -21 - 10 + 12 = -19\). This equation is valid.
05
Verify the Second Equation of System b
Next, substitute into the second equation: \(3x - 2y = -23\). Calculate: \(3(-7) - 2(5) = -21 - 10 = -31\). This equation does not hold true as it should be \(-23\).
06
Check the Third Equation of System b
Finally, substitute into the third equation: \(8x - y + 4z = -58\). Check: \(8(-7) - 5 + 4(\frac{3}{4}) = -56 - 5 + 3 = -58\). Here, the equation holds true.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Solution Verification
When working with systems of equations, one essential skill is verifying whether a proposed solution is correct. This process ensures that the values given for the variables satisfy each equation in the system. You'll typically follow these steps to verify a solution:
- Substitute the given values into each equation independently.
- Simplify the equation to confirm whether both sides are equal.
- If each equation in the system is satisfied, then the solution is correct.
- If even one equation is not satisfied, the values do not make up a solution to the system.
Substitution Method
The substitution method is one way to solve systems of equations. This method is helpful because it focuses on solving one equation for a single variable and then using that expression to substitute into the other equations. While our exercise focused on verification, understanding substitution helps in finding solutions when not given a potential answer initially.
To use the substitution method:
- Choose one equation and solve it for one variable in terms of the others.
- Substitute this expression into the other equations.
- Solve the resulting equations, which now have fewer variables.
- Continue simplifying until you can find specific values for all variables.
Linear Equations
Linear equations are fundamental elements of algebra and form the backbone of systems of equations. A linear equation is of the form:\[ ax + by + cz = d \]where \(a\), \(b\), and \(c\) are coefficients and \(d\) is a constant term. Each equation describes a straight line in a two-dimensional space, and a plane in three-dimensional space, or more complex geometric objects in higher dimensions.When placed in a system:
- Multiple linear equations interact and the solution set is where their graphs intersect.
- Two linear equations intersect at a single point, multiple times depending on the dimension, or not at all.
- Solving these systems often means finding the common intersection of all involved equations.