GARDENING HELPERS
Posted on Saturday, April 19th, 2008 at 4:15 pm
math helpers please HELP ME!?!?
Directions for Problems 1–3: Solve each equation, if possible. Write irrational numbers in simplest radical form. Describe the strategy you used to get your solution and tell why you chose that strategy.
1) x^2 – 6x + 1 = 0
2) x^2 + 4 = 0
3) x^2 – 5x – 7 = 0
4) The perimeter of a rectangular flower garden is 94 m and its area is 480 m2. Find the length of the garden.
(1) complete square since its obvious
(x-3)^2 = 8
x= 3 +/- 2 sqrt(2)
(2) if you have done complex numbers x = +- 2 i
if not, no real solutions
(3) I always prefer completing square to formula
(x – 5/2)^2 = 7 + 25/4 = 53/4
x = 5/2 +/- sqrt(53)/2
(4)
l+w = 47
lw = 480 = l(47-l)
l^2 – 47l + 480 = 0
(l-47/2)^2 = (47/2)^2 – 480 = 289/4
l = 47/2 +/- 17/2
one solution will be length other width (and we normally take length > width )
so length = 32
John Dromgoole home-made garden helpers: Central Texas Garde