Δx (delta x) is about a secant line, a line between two points representing the rate of change between those two points. That's a "differential" (between the two points).
dx is about a tangent line to one point, representing an instantaneous rate of change. That makes it a "derivative."
Answer: 15x^2+6x-20
Step-by-step explanation:
use symbolab.com for calculator and further steps
d/dx (5x+3)5
((x-2)(x+2))=2x
5(x-2)(x+2)+2x(5x+3)
15x^2=6x-20