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What is the solution to this system of equations?

-a – 3 + 4c = 3
5a - 8b + 5c = 27
5a – 2b + 6c = 1
A. a = -4, b = -2, c = 1
B. a = 4, b = 2, c = -1
C. a = 1, b = -4, c = -2
D. a = -2, b = –1, c = 4

User Eeglbalazs
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2 Answers

26 votes
26 votes

Final answer:

To solve the system of equations, we can use the method of substitution. By substituting the values of a and b in terms of c, and solving for c, we find c = -1. Substituting this value of c back into the equations, we can find the values of a and b which are a = -10 and b = -7/4 respectively.

Step-by-step explanation:

To solve the system of equations:

-a - 3 + 4c = 3

5a - 8b + 5c = 27

5a - 2b + 6c = 1

We can solve this system using the method of elimination or substitution. Let's use the method of substitution.

From the first equation, we can solve for a: a = -6 + 4c

Substitute this value of a in the second equation: 5(-6 + 4c) - 8b + 5c = 27

Simplify and solve for b: -30 + 20c - 8b + 5c = 27

Combine like terms: -30 + 27 + 20c + 5c - 8b = 0

Simplify further: -3 + 25c - 8b = 0

From the third equation, solve for a: a = -5 + 2b - 6c

Substitute this value of a in the second equation: 5(-5 + 2b - 6c) - 8b + 5c = 27

Simplify and solve for c: -25 + 10b - 30c - 8b + 5c = 27

Combine like terms: -25 + 27 + 10b - 8b - 30c + 5c = 0

Simplify further: 2b - 25c + 2 = 0

We now have the system of equations:

-3 + 25c - 8b = 0

2b - 25c + 2 = 0

We can solve this system of equations using the method of elimination.

Multiply the first equation by 2: -6 + 50c - 16b = 0

Add this equation to the second equation: -6 + 50c - 16b + 2b - 25c + 2 = 0

Combine like terms: -4b + 25c - 4 = 0

Solve for b: b = (25c - 4)/4

Substitute this value of b in the first equation: -3 + 25c - 8((25c - 4)/4) = 0

Simplify and solve for c: -3 + 25c - 50c + 8 = 0

Combine like terms: 5c - 3 + 8 = 0

Simplify further: 5c + 5 = 0

Solve for c: c = -1

Substitute this value of c in the first equation: -a - 3 + 4(-1) = 3

Simplify and solve for a: -a - 3 - 4 = 3

Combine like terms: -a - 7 = 3

Solve for a: a = -10

The solution to the system of equations is a = -10, b = (25(-1) - 4)/4 = -7/4, and c = -1. Therefore, the correct option is a = -10, b = -7/4, c = -1.

User Ziwon
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26 votes
26 votes

Step-by-step explanation:

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What is the solution to this system of equations? -a – 3 + 4c = 3 5a - 8b + 5c = 27 5a-example-1
User Koenmetsu
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