What are the real roots of 3x^3+28x^2+65x=0?

Ineed i do not understand i'm only 8

The perimiter of a rectangle is 70 inches the legneth of the rectangle is 5 less than 3 times the width of the rectangle what is the width of the rectangle

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2