Find Decreasing Intervals for y = (x+2)²: Quadratic Function Analysis

To solve this problem, we'll assess the function $y = (x+2)^2$.

Step 1: Identify the vertex.
The given function is $y = (x+2)^2$, which is in the form $(x-h)^2 + k$. Here, $h = -2$ and $k = 0$, so the vertex is $(-2, 0)$.

Step 2: Determine the orientation of the parabola.
In the expression $y = (x+2)^2$, the coefficient of the square term $a = 1$ is positive, indicating the parabola opens upwards.

Step 3: Identify the decreasing interval.
For a parabola that opens upwards, the function is decreasing to the left of the vertex. The vertex at $x = -2$ marks the transition point from decreasing to increasing.

Therefore, the function $y = (x+2)^2$ is decreasing for $x < -2$.

The correct answer is: $x<-2$