Find two numbers whose sum is 6 and product is 14?
回答 (4)
2015-08-30 10:12 pm
x+y = 6
y = 6-x
xy = 14
x(6-x) = 14
6x - x² = 14
x² - 6x + 14 = 0
quadratic formula
x = [6 ± √(6² – 4·1·14)] / [2·1]
= [6 ± √(-20)] / 2
= [6 ± (2√5)i] / 2
= 3 ± (√5)i
x = 3 + √5i
y = 3 - √5i
y = 6-x
xy = 14
x(6-x) = 14
6x - x² = 14
x² - 6x + 14 = 0
quadratic formula
x = [6 ± √(6² – 4·1·14)] / [2·1]
= [6 ± √(-20)] / 2
= [6 ± (2√5)i] / 2
= 3 ± (√5)i
x = 3 + √5i
y = 3 - √5i
2015-08-31 1:08 am
x + y = 6
xy = 14
x(6 - x) = 14
x^2 - 6x + 14 = 0
Complex solutions:
x = 3 - 2.2361 i
x = 3 + 2.2361 i
xy = 14
x(6 - x) = 14
x^2 - 6x + 14 = 0
Complex solutions:
x = 3 - 2.2361 i
x = 3 + 2.2361 i
2015-08-30 10:14 pm
No whole numbers for this.
2015-08-30 10:13 pm
you have x y = 14 and x + y = 6---> y = 6 - x ---> 6 x - x² = 14---> x² - 6x + 14 = 0----> x = 3 ± i √5...thus no real number exists for an answer
收錄日期: 2021-04-21 13:51:27
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