Solve the equation: 38x²-9x-5=0?

2008-02-22 5:53 pm
(use a comma to separate answers as needed)

回答 (9)

2008-02-22 5:57 pm
✔ 最佳答案
Factor first:

(19x + 5) * (2x - 1) = 0

Now just read off the roots

x = {-5/19, 1/2}
2008-02-23 7:02 am
(19x + 5)(2x - 1) = 0
x = - 5 / 19 , x = 1 / 2
2008-02-23 2:00 am
the answer is (19x+5)(2x-1)
then
19x+5=0 2x-1=0
19x=-5 2x=1
x=-5/19 x=1/2
2008-02-23 1:59 am
Not even going to try to factor that - I'll go right to the quadratic equation:

x = [ -b ± √(b² - 4ac)] / 2a
x = [ -(-9) ± √((-9)² - 4(38)(-5))] / 2(38)
x = [ 9 ± √(81 + 760)] / 76
x = [ 9 ± √(841)] / 76
x = [ 9 ± 29 ] / 76
x = (9 + 29) / 76, (9 - 29) / 76
x = 38 / 76, -20 / 76
x = 1/2, -5/19
2008-02-23 1:59 am
38x^2 - 9x - 5 = 0
(2x - 1)(19x + 5) = 0

2x - 1 = 0
2x = 1
x = 1/2

19x + 5 = 0
19x = -5
x = -5/19

∴ x = 1/2 , x = -5/19
2008-02-23 1:57 am
It factors (19x +5 )(2x -1) =0
x = -5/19, 1/2
2008-02-23 1:57 am
(19x + 5)(2x - 1) = 0

19x + 5 = 0 or 2x - 1=0

19x=-5 or 2x=1

x = -5/19, x = 1/2
2008-02-23 1:56 am
(19x+5)(2x-1)=0
x=-5/19, 1/2
2008-02-23 1:59 am
factors of 38: (1, 2, 19, 38)
factors of 5: (1, 5)

(19x + 5) (2x - 1) = 0

19x + 5 = 0 /// and /// 2x-1 = 0

19x+5=0
19x=-5
x= -5/19

2x-1=0
2x=1
x=1/2

x= -5/19 , 1/2


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