Answer: g = 2
We can find the value of g by expanding the left hand side of the equation and comparing the left side with right side.
[tex](x-3)(x+5)= x^{2} +gx-15 \\ \\
x^{2} +5x-3x-15= x^{2} +gx-15 \\ \\
x^{2} +2x-15= x^{2} +gx-15[/tex]
Comparing the two sides of the equation, we can conclude that the value of g is 2. Therefore correct answer is 3rd option
