Question 983388
The area of the rectangle is represented by 5x^2 + 19x + 12. 

Width=5x + 4


{{{5x^2 + 19x + 12}}}

{{{5x^2+15x+4x+12}}}

{{{5x(x+3)+4(x+3)}}}

{{{(5x+4)(X+3)}}}

Area = L * W

{{{(5x+4)(X+3)}}}= L * (5x+4)

l= {{{((5x+4)(X+3)/(5x+4))}}}

length = (x+3)