Questions: Solve the following system of equations by the substitution method. Check the solutions.
y = x^2
y = x + 2
Transcript text: Solve the following system of equations by the substitution method. Check the solutions.
\[
\left\{\begin{array}{l}
y=x^{2} \\
y=x+2
\end{array}\right.
\]
Solution
Solution Steps
To solve the system of equations using the substitution method, we will:
Substitute \( y = x^2 \) from the first equation into the second equation \( y = x + 2 \).
Solve the resulting quadratic equation for \( x \).
Substitute the values of \( x \) back into either original equation to find the corresponding \( y \) values.
Check the solutions by substituting the values back into both original equations.
Step 1: Set Up the System of Equations
We start with the following system of equations:
\[
\begin{cases}
y = x^2 \quad (1) \\
y = x + 2 \quad (2)
\end{cases}
\]
Step 2: Substitute and Solve for \( x \)
We substitute \( y \) from equation (1) into equation (2):
\[
x^2 = x + 2
\]
Rearranging gives us the quadratic equation:
\[
x^2 - x - 2 = 0
\]
Factoring this equation, we find:
\[
(x + 1)(x - 2) = 0
\]
Thus, the solutions for \( x \) are:
\[
x = -1 \quad \text{and} \quad x = 2
\]
Step 3: Find Corresponding \( y \) Values
Next, we substitute the values of \( x \) back into equation (1) to find the corresponding \( y \) values:
For \( x = -1 \):
\[
y = (-1)^2 = 1
\]
So, one solution is \( (-1, 1) \).
For \( x = 2 \):
\[
y = (2)^2 = 4
\]
So, another solution is \( (2, 4) \).
Step 4: Verify the Solutions
We check both solutions against the original equations:
For \( (-1, 1) \):
Equation (1): \( 1 = (-1)^2 \) is true.
Equation (2): \( 1 = -1 + 2 \) is true.
For \( (2, 4) \):
Equation (1): \( 4 = (2)^2 \) is true.
Equation (2): \( 4 = 2 + 2 \) is true.
Both solutions satisfy the original equations.
Final Answer
The solution set is:
\[
\boxed{(-1, 1), (2, 4)}
\]