the graph of the function $f(x) = (x +2)(x + 6)$ is shown below.\nwhat is true about the domain and range of…

the graph of the function $f(x) = (x +2)(x + 6)$ is shown below.\nwhat is true about the domain and range of the function?\n○ the domain is all real numbers, and the range is all real numbers greater than or equal to $-4$.\n○ the domain is all real numbers greater than or equal to $-4$, and the range is all real numbers.\n○ the domain is all real numbers such that $-6 \\leq x \\leq -2$, and the range is all real numbers greater than or equal to $-4$.\n○ the domain is all real numbers greater than or equal to $-4$, and the range is all real numbers such that $-6 \\leq x \\leq -2$.
Answer
Explanation:
Step1: Identify function type
The function $f(x)=(x+2)(x+6)$ is a quadratic polynomial, which expands to $f(x)=x^2+8x+12$. Quadratic functions have no restrictions on input real numbers, so the domain is all real numbers.
Step2: Find vertex (minimum value)
For a quadratic function in the form $f(x)=ax^2+bx+c$, the x-coordinate of the vertex is $x=-\frac{b}{2a}$. Here, $a=1$, $b=8$, so: $x=-\frac{8}{2\times1}=-4$ Substitute $x=-4$ into the function to find the minimum y-value: $f(-4)=(-4+2)(-4+6)=(-2)(2)=-4$ Since $a=1>0$, the parabola opens upward, so the range is all real numbers greater than or equal to -4.
Step3: Match with options
This matches the first option.
Answer:
The domain is all real numbers, and the range is all real numbers greater than or equal to $-4$.