Answer:
10x^3 + 6x^2 + 5x + 3
Step-by-step explanation:
F(x)=(5x+3)(2x^2+1)
= 5x*2x^2 + 5x*1 + 3*2x^2 + 3*1
= 10x^3 + 5x + 6x^2 + 3
= 10x^3 + 6x^2 + 5x + 3
The constant of proportionality is equal to k in y=kx. In y=10x, the k value is 10.
Final answer: C. 10