Answer with explanation:
⇒Domain:
f(x)= -x² -2 x +15
= - (x²+2 x -15)
Splitting the middle term
= - (x²+5 x - 3 x -15)
= -[ x × (x+5) -3× (x+5)]
= -(x-3)(x+5)
y=f(x)=(3 -x)(x+5)
Domain of the function is defined as set of all values of x, for which y is defined.
f(x) is defined as all real values of x.So, Domain = R.
⇒Range:
![y=-x^2-2 x +15\\\\y=-(x^2+2 x-15)\\\\ y=-[(x+1)^2-1-15]\\\\y= -(x+1)^2+16\\\\ 16 -y=(x+1)^2\\\\x+1=\pm\sqrt{16-y}\\\\x=\pm\sqrt{16-y}-1](https://tex.z-dn.net/?f=y%3D-x%5E2-2%20x%20%2B15%5C%5C%5C%5Cy%3D-%28x%5E2%2B2%20x-15%29%5C%5C%5C%5C%20y%3D-%5B%28x%2B1%29%5E2-1-15%5D%5C%5C%5C%5Cy%3D%20-%28x%2B1%29%5E2%2B16%5C%5C%5C%5C%2016%20-y%3D%28x%2B1%29%5E2%5C%5C%5C%5Cx%2B1%3D%5Cpm%5Csqrt%7B16-y%7D%5C%5C%5C%5Cx%3D%5Cpm%5Csqrt%7B16-y%7D-1)
Range of the function is defined as set of all values of y, for which x is defined.
⇒16 -y ≥ 0
⇒y ≤ 16
Option B
The domain is all real numbers. The range is {y|y ≤ 16}.