Question
Use the substitution method to solve the system x equals y minus 4, x + 8y = 2
Negative 3 1/3, 2/3
2/3, -3 and 1/3
Infinite solutions
No solutions
Negative 3 1/3, 2/3
2/3, -3 and 1/3
Infinite solutions
No solutions
Answers
Answered by
GPT-4o mini
To solve the system of equations using the substitution method, we'll start with the two equations given:
1. \( x = y - 4 \)
2. \( x + 8y = 2 \)
Now, we can substitute the expression for \( x \) from the first equation into the second equation.
Substituting \( x \) in the second equation:
\[
(y - 4) + 8y = 2
\]
Now, simplify the equation:
\[
y - 4 + 8y = 2
\]
Combine like terms:
\[
9y - 4 = 2
\]
Now, add 4 to both sides:
\[
9y = 6
\]
Divide both sides by 9:
\[
y = \frac{6}{9} = \frac{2}{3}
\]
Now, we can find \( x \) using the first equation \( x = y - 4 \):
\[
x = \frac{2}{3} - 4
\]
To subtract, it's helpful to convert 4 into a fraction:
\[
x = \frac{2}{3} - \frac{12}{3} = \frac{2 - 12}{3} = \frac{-10}{3}
\]
So we have found:
\[
x = -\frac{10}{3}, \quad y = \frac{2}{3}
\]
Thus the solution to the system of equations is:
\[
\left( -\frac{10}{3}, \frac{2}{3} \right)
\]
Reviewing the provided answer choices:
- Negative 3 1/3, 2/3
- 2/3, -3 and 1/3
- Infinite solutions
- No solutions
The correct answer, matching our solution, is:
**Negative 3 1/3, 2/3** (equivalently, \( -\frac{10}{3}, \frac{2}{3} \)).
1. \( x = y - 4 \)
2. \( x + 8y = 2 \)
Now, we can substitute the expression for \( x \) from the first equation into the second equation.
Substituting \( x \) in the second equation:
\[
(y - 4) + 8y = 2
\]
Now, simplify the equation:
\[
y - 4 + 8y = 2
\]
Combine like terms:
\[
9y - 4 = 2
\]
Now, add 4 to both sides:
\[
9y = 6
\]
Divide both sides by 9:
\[
y = \frac{6}{9} = \frac{2}{3}
\]
Now, we can find \( x \) using the first equation \( x = y - 4 \):
\[
x = \frac{2}{3} - 4
\]
To subtract, it's helpful to convert 4 into a fraction:
\[
x = \frac{2}{3} - \frac{12}{3} = \frac{2 - 12}{3} = \frac{-10}{3}
\]
So we have found:
\[
x = -\frac{10}{3}, \quad y = \frac{2}{3}
\]
Thus the solution to the system of equations is:
\[
\left( -\frac{10}{3}, \frac{2}{3} \right)
\]
Reviewing the provided answer choices:
- Negative 3 1/3, 2/3
- 2/3, -3 and 1/3
- Infinite solutions
- No solutions
The correct answer, matching our solution, is:
**Negative 3 1/3, 2/3** (equivalently, \( -\frac{10}{3}, \frac{2}{3} \)).