Questions: Solve for (y), where (y) is a real number.
[
sqrt-y+30=y
]
(If there is more than one solution, separate them with commas.)
Transcript text: Solve for $y$, where $y$ is a real number.
\[
\sqrt{-y+30}=y
\]
(If there is more than one solution, separate them with commas.)
Solution
Solution Steps
To solve the equation \(\sqrt{-y + 30} = y\), we need to isolate \(y\). We can start by squaring both sides to eliminate the square root, then solve the resulting quadratic equation.
Step 1: Set Up the Equation
We start with the given equation:
\[
\sqrt{-y + 30} = y
\]
Step 2: Square Both Sides
To eliminate the square root, we square both sides of the equation:
\[
(\sqrt{-y + 30})^2 = y^2
\]
This simplifies to:
\[
-y + 30 = y^2
\]
Step 3: Rearrange into a Standard Quadratic Equation
Rearrange the equation to form a standard quadratic equation:
\[
y^2 + y - 30 = 0
\]
Step 4: Solve the Quadratic Equation
We solve the quadratic equation \(y^2 + y - 30 = 0\) using the quadratic formula:
\[
y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
\]
where \(a = 1\), \(b = 1\), and \(c = -30\). Plugging in these values, we get:
\[
y = \frac{-1 \pm \sqrt{1^2 - 4 \cdot 1 \cdot (-30)}}{2 \cdot 1}
\]
\[
y = \frac{-1 \pm \sqrt{1 + 120}}{2}
\]
\[
y = \frac{-1 \pm \sqrt{121}}{2}
\]
\[
y = \frac{-1 \pm 11}{2}
\]
Step 5: Find the Real Solutions
Solving for \(y\), we get two potential solutions:
\[
y = \frac{-1 + 11}{2} = 5
\]
\[
y = \frac{-1 - 11}{2} = -6
\]
Step 6: Verify the Solutions
We need to verify which of these solutions satisfy the original equation \(\sqrt{-y + 30} = y\):
For \(y = 5\):
\[
\sqrt{-5 + 30} = \sqrt{25} = 5
\]
This is true.
For \(y = -6\):
\[
\sqrt{-(-6) + 30} = \sqrt{36} = 6
\]
This does not equal \(-6\), so it is not a valid solution.