Welcome to Westonci.ca, where your questions are met with accurate answers from a community of experts and enthusiasts. Explore a wealth of knowledge from professionals across different disciplines on our comprehensive platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Solve the system of equations using substitution and identify the solution. List your answers alphabetically in the ordered pairs.

[tex]\[
\begin{array}{l}
2c - d = -2 \\
4c + d = 20
\end{array}
\][/tex]

A. [tex]\((20, 9)\)[/tex]
B. [tex]\((3, 8)\)[/tex]
C. [tex]\((9, 20)\)[/tex]
D. [tex]\((8, 3)\)[/tex]
E. No Solution
F. Infinitely Many Solutions


Sagot :

To solve the system of equations using substitution, follow these steps:

1. Write down the equations:
[tex]\[ \begin{array}{l} 2c - d = -2 \quad \text{(Equation 1)} \\ 4c + d = 20 \quad \text{(Equation 2)} \end{array} \][/tex]

2. Solve Equation 1 for [tex]\( d \)[/tex]:
[tex]\[ 2c - d = -2 \implies d = 2c + 2 \][/tex]

3. Substitute [tex]\( d = 2c + 2 \)[/tex] into Equation 2:
[tex]\[ 4c + (2c + 2) = 20 \][/tex]

4. Combine like terms:
[tex]\[ 4c + 2c + 2 = 20 \implies 6c + 2 = 20 \][/tex]

5. Solve for [tex]\( c \)[/tex]:
[tex]\[ 6c + 2 = 20 \implies 6c = 18 \implies c = 3 \][/tex]

6. Substitute [tex]\( c = 3 \)[/tex] back into the expression for [tex]\( d \)[/tex]:
[tex]\[ d = 2c + 2 \implies d = 2(3) + 2 \implies d = 6 + 2 \implies d = 8 \][/tex]

7. Write the solution as an ordered pair:
[tex]\[ (c, d) = (3, 8) \][/tex]

8. Verify the solution:
Substitute [tex]\( c = 3 \)[/tex] and [tex]\( d = 8 \)[/tex] back into the original equations to ensure both are satisfied:
- For Equation 1: [tex]\( 2(3) - 8 = 6 - 8 = -2 \)[/tex] (True)
- For Equation 2: [tex]\( 4(3) + 8 = 12 + 8 = 20 \)[/tex] (True)

Since both equations are satisfied, the solution to the system of equations is [tex]\( (3, 8) \)[/tex].

Therefore, the correct answer is:
[tex]\[ (3, 8) \][/tex]