A rectangular piece of sheet metal is 4 ft longer than it is wide. (See the illustration in the link below.) The area of the piece of sheet metal is 12 ft^2. Find its length and width.
www.webassign.net/ewenmath10/11-3-003-alt.gif
length =x+4
width =x
x(x+4)=12
x^2+4x-12=0
x^2-2x+6x-12=0
x(x-2)+6(x-2)=0
(x+6)(x-2)=0
length = 6
width = 2
is my answer correct?
I would have included the restriction on the variable x
namely x>0
at the end your correct solution ....
(x+6)(x-2)=0
so x = -6, or x = 2
you might have stated, (I would have insisted on it), that x = -6 is inadmissible
and your answer comes from x = 2