IDNLearn.com connects you with experts who provide accurate and reliable answers. Our experts are available to provide accurate, comprehensive answers to help you make informed decisions about any topic or issue you encounter.

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]