It's the quadratic formula, I just simplifies some of it already
(-10+/- sqr root of 420)/-8
2006-08-05 23:48:08 · 9 answers · asked by #15mwu 5 in Science & Mathematics ➔ Mathematics
spelling error: *simplified
2006-08-05 23:48:39 · update #1
(-10 ± sqrt(420))/(-8)
(-10 ± sqrt(4 * 105))/(-8)
(-10 ± 2sqrt(105))/(-8)
(1/4)(5 ± sqrt(105))
assuming that that your problem is
-4x^2 + 10x + 20
which could be simplified to
-2(2x^2 - 5x - 10) = 0
x = (-(-5) ± sqrt((-5)^2 - 4(2)(-10)))/(2(2))
x = (5 ± sqrt(25 + 80))/4
x = (5 ± sqrt(105))/4
x = (1/4)(5 ± sqrt(105))
2006-08-06 03:38:21 · answer #1 · answered by Sherman81 6 · 0⤊ 0⤋
divide per -2 the numeratror and denominator:
sqrt(420)= 2 sqrt(105)= 2 sqrt(5*3*7)
so = (5 +/- sqrt(105))/4
2006-08-06 06:57:58 · answer #2 · answered by fred 055 4 · 0⤊ 0⤋
sqrrt of 420 is 2 radical 105
-10 +/- 2 sqrrt 105 / -8
Divide each factor by -2
5 +/- radical 105 /4
2006-08-06 07:33:07 · answer #3 · answered by MollyMAM 6 · 0⤊ 0⤋
=i, ( where i= -1).
2006-08-06 06:52:51 · answer #4 · answered by Anonymous · 0⤊ 0⤋
(5/4)+/-(2*sqrt105)
2006-08-06 06:54:21 · answer #5 · answered by KiKi 2 · 0⤊ 0⤋
(-10+/-20.4939)/-8=
-30.4939/-8 or -10.4939/-8=
3.8117 or 1.0494
2006-08-06 07:43:44 · answer #6 · answered by Anonymous · 0⤊ 0⤋
erm (5/4)+/-(2x square-root105)
2006-08-06 06:56:02 · answer #7 · answered by Miss LaStrange 5 · 0⤊ 0⤋
Just call it "X"
2006-08-06 06:52:54 · answer #8 · answered by B 6 · 0⤊ 0⤋
3.811737691.............^_^
2006-08-06 06:57:09 · answer #9 · answered by charyz 1 · 0⤊ 0⤋