(2x -1)*(x - 2) = 20, solve for x
(x - 2) (2 x - 1) = 20
Expand out terms of the left hand side:
2 x^2 - 5 x + 2 = 20
Divide both sides by 2:
x^2 - (5 x)/2 + 1 = 10
Subtract 1 from both sides:
x^2 - (5 x)/2 = 9
Add 25/16 to both sides:
x^2 - (5 x)/2 + 25/16 = 169/16
Write the left hand side as a square:
(x - 5/4)^2 = 169/16
Take the square root of both sides:
x - 5/4 = 13/4 or x - 5/4 = -13/4
Add 5/4 to both sides:
x = 9/2 or x - 5/4 = -13/4
Add 5/4 to both sides:
x = 9/2 * 2 - 1 = 8 units. or x = -2(Discard this one)
+128448 We have
Area = L * W
20 = (2x - 1) (x - 2) simplify
20 = 2x^2 - x - 4x + 2 subtract 20 from both sides and we have
2x^2 - 5x - 18 = 0 factor
(2x - 9) ( x + 2) = 0
Only the first factor set to 0 will yield a positive result for x
2x - 9 = 0
2x = 9
x = 9/2
So....the length is 2(9/2) - 1 = 9 - 1 = 8
