write a polynomial for the area. then write an equation and use it to find the lenght and with. PLEASE HELP?

Question

Problem:
Length of rectangle 3x+2
then one x on each lenght and an awnser in middle of rectangle
A=120

Answer 1

so width = x?
so (3x+2)*x=120
3x^2+2x=120
3x^2+2x-120=0
(3x+20)(x-6)=0
the only one that will make sense is x-6=0, x=6 the other will give us a negative

Answer 2

(3x+2)x =120
3x^2+2x =120
3x^2+2x -120
x = [-2 +/- sqrt(2^2 +1440)]/6
x = (-2 +/- 38)/6
x = 6 = width
3x+2 = 20 = length