To find the vertex of a quadratic function in the form \( f(x) = ax^2 + bx + c \), we use the vertex formula \( x = -\frac{b}{2a} \) to find the x-coordinate of the vertex. Then, we substitute this x-coordinate back into the function to find the corresponding y-coordinate.
Step 1: Identify the coefficients
Given the quadratic function \( f(x) = x^2 + 3x + 4 \), we identify the coefficients:
\( a = 1 \)
\( b = 3 \)
\( c = 4 \)
Step 2: Calculate the x-coordinate of the vertex
The x-coordinate of the vertex for a quadratic function \( f(x) = ax^2 + bx + c \) is given by:
\[
x = -\frac{b}{2a}
\]
Substituting the values of \( a \) and \( b \):
\[
x = -\frac{3}{2 \cdot 1} = -\frac{3}{2} = -1.5
\]
Step 3: Calculate the y-coordinate of the vertex
To find the y-coordinate, substitute \( x = -1.5 \) back into the function \( f(x) \):
\[
f(-1.5) = (1)(-1.5)^2 + (3)(-1.5) + 4
\]
\[
= 2.25 - 4.5 + 4
\]
\[
= 1.75
\]