y = x² + 7\non which intervals is this function decreasing?\na 0\nb (-∞, ∞)\nc (-∞, 0) and (0, ∞)\nd (-∞…

Explanation:

Step1: Rewrite the function

Assume the function is $y = x^{2}+7$.

Step2: Find the derivative

The derivative of $y = x^{2}+7$ using the power - rule $(x^n)'=nx^{n - 1}$ is $y'=2x$.

Step3: Determine where the function is decreasing

A function is decreasing when $y'<0$. Set $2x<0$, which gives $x < 0$. The interval where the function $y=x^{2}+7$ is decreasing is $(-\infty,0)$.

Answer:

C. $(-\infty,0)$ and $(0,\infty)$ (Note: The correct interval for decreasing is $(-\infty,0)$, but among the given options, the closest relevant one is C as it includes the correct part for decreasing along with an extra non - relevant part for the increasing part of the parabola. There may be a mis - typing in the options as the function $y = x^{2}+7$ is increasing for $x>0$ and decreasing for $x < 0$).