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solve x (squared) + 6x + 7 = 0?
2009-04-22 7:37 am
回答 (4)
2009-04-22 7:50 am
✔ 最佳答案
x² + 6x + 7 = 0Using the formula:
. . . . . . . __________
. . . -6 ± √6² - 4(1)(7)
x = ––––––––––––––––
. . . . . . . . 2(1)
. . . . . . . _______
. . . -6 ± √36 - 28
. = ––––––––––––
. . . . . . . . 2
. . . . . . . __
. . . -6 ± √8
. = ––––––––
. . . . . .2
. . . . . . . _____
. . . -6 ± √4 × 2
. = ––––––––––
. . . . . . .2
. . . . . . . _ . . _
. . . -6 ± √4 ×√2
. = –––––––––––
. . . . . . . 2
. . . . . . . . _
. . . -6 ± 2√2
. = ––––––––
. . . . . .2
. . . . . . . . ._
. . . 2(-3 ± √2)
. = –––––––––
. . . . . .2
. . . . . . ._
. = -3 ± √2
. . . . . . ._. . . . . _
. = -3 + √2, -3 - √2
So the answer is D
Done
2009-04-22 10:05 am
x^2 + 6x + 7 = 0
x = [-b 屉(b^2 - 4ac)]/2a
a = 1
b = 6
c = 7
x = [-6 屉(36 - 28)]/2
x = [-6 屉8]/2
x = [-6 屉(2^2 * 2)]/2
x = [-6 ±2â2]/2
x = -3 屉2
â´ x = -3 ±â2
(answer D)
x = [-b 屉(b^2 - 4ac)]/2a
a = 1
b = 6
c = 7
x = [-6 屉(36 - 28)]/2
x = [-6 屉8]/2
x = [-6 屉(2^2 * 2)]/2
x = [-6 ±2â2]/2
x = -3 屉2
â´ x = -3 ±â2
(answer D)
2009-04-22 7:44 am
the roots are gonna be = (-6+ sqrt(36-28))/2 an (-6-sqrt(36-28))/2
the answer's (d)
the roots of a quadratic are given as (-b +or- sqrt(b^2 - 4ac))/2a
the answer's (d)
the roots of a quadratic are given as (-b +or- sqrt(b^2 - 4ac))/2a
2009-04-22 7:42 am
x = [ - 6 ± â (36 - 28 ) ] / 2
x = [ - 6 ± â (8) ] / 2
x = [ - 6 ± 2â 2 ] / 2
x = - 3 ± â 2
OPTION D
x = [ - 6 ± â (8) ] / 2
x = [ - 6 ± 2â 2 ] / 2
x = - 3 ± â 2
OPTION D
收錄日期: 2021-05-01 12:17:40
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090421233737AAA12Cd