Question 314897
"A rectangular cutting board is 6 inches longer than it is wide. If the area of the cutting board is 216 square inches, find the length and the width. I figured finding the square root would help a bit, sqrt or 216 is about 14.7, i tried to subtract 6 then add six and i just made myself confused."

area of a rectangle A = length L * width W
A = (W + 6) * W = 216 (length is 6 inches longer than width)
A = W^2 + 6W = 216
W^2 + 6W - 216 = 0 (solve for W, throw out negative answer)
{{{W = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
a = 1, b = 6, c = -216
{{{W = (-6 +- sqrt( 36 - 4*(-216) ))/2 }}}
{{{W = (-6 +- sqrt(36 + 864))/2 }}}
{{{W = (-6 +- sqrt(900))/2 }}}
{{{W = (-6 +- 30)/2 }}}
W = (-6 + 30)/2 or W = (-6 - 30)/2
W = 24/2 = 12 or W = -36/2 = -18
W = 12 since W can not be negative
18 * 12 = 216