Questions: Solve the following equation by making an appropriate substitution.
x^-2+6 x^-1+5=0
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The solution set is . (Use a comma to separate answers as needed.)
B. The solution set is the empty set.
Transcript text: Solve the following equation by making an appropriate substitution.
\[
x^{-2}+6 x^{-1}+5=0
\]
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The solution set is $\{\square$. (Use a comma to separate answers as needed.)
B. The solution set is the empty set.
Solution
Solution Steps
Step 1: Substitution
We start with the equation
\[
x^{-2} + 6x^{-1} + 5 = 0.
\]
To simplify this equation, we make the substitution
\[
y = x^{-1}.
\]
This transforms the equation into
\[
y^2 + 6y + 5 = 0.
\]
Step 2: Solve the Quadratic Equation
Next, we solve the quadratic equation
\[
y^2 + 6y + 5 = 0.
\]
Factoring the quadratic, we find the solutions for \( y \):
\[
(y + 5)(y + 1) = 0.
\]
Thus, the solutions are
\[
y = -5 \quad \text{and} \quad y = -1.
\]
Step 3: Back Substitution
Now, we substitute back to find the values of \( x \) using \( y = x^{-1} \):
For \( y = -5 \):
\[
x^{-1} = -5 \implies x = -\frac{1}{5}.
\]
For \( y = -1 \):
\[
x^{-1} = -1 \implies x = -1.
\]