Can anyone help me with this problem?
回答 (6)
2008-08-19 3:55 pm
✔ 最佳答案
3x^2 - 11x - 20 = 0Factor:
(3x+4)(x-5) = 0
3x+4 = 0
3x = -4
x = -4/3
x-5 = 0
x=5
So the answer are:
x = -4/3 or x = 5
2008-08-20 12:17 am
3x^2 - 11x - 20 = 0
3x^2 + 4x - 15x - 20 = 0
(3x^2 + 4x) - (15x + 20) = 0
x(3x + 4) - 5(3x + 4) = 0
(3x + 4)(x - 5) = 0
3x + 4 = 0
3x = -4
x = -4/3
x - 5 = 0
x = 5
â´ x = -4/3 , 5
3x^2 + 4x - 15x - 20 = 0
(3x^2 + 4x) - (15x + 20) = 0
x(3x + 4) - 5(3x + 4) = 0
(3x + 4)(x - 5) = 0
3x + 4 = 0
3x = -4
x = -4/3
x - 5 = 0
x = 5
â´ x = -4/3 , 5
2008-08-19 11:02 pm
6x^2-11x-20=0
This equation is of form ax^2+bx+c=0
a = 6 b = -11 c = -20
x=[-b+/-sqrt(b^2-4ac)]/2a]
x=[11 +/-sqrt(-11^2-4(6)(-20)]/(2)(6)
discriminant is b^2-4ac =601
x=[11 +â(601)] / (2)(6)
x=[11 -â(601)] / (2)(6)
x=[11+24.515301344262525] / 12
x=[11-24.515301344262525] / 12
The roots are 2.9596 and -1.1263
This equation is of form ax^2+bx+c=0
a = 6 b = -11 c = -20
x=[-b+/-sqrt(b^2-4ac)]/2a]
x=[11 +/-sqrt(-11^2-4(6)(-20)]/(2)(6)
discriminant is b^2-4ac =601
x=[11 +â(601)] / (2)(6)
x=[11 -â(601)] / (2)(6)
x=[11+24.515301344262525] / 12
x=[11-24.515301344262525] / 12
The roots are 2.9596 and -1.1263
2008-08-19 11:00 pm
3x^2 - 11x - 20 = 0
Now LOOK here: 3 x 20 = 60 ; 60 = 15 x 4 & 15 - 4 = 11
so we have,
3x^2 - (15 - 4)x - 20 = 0
=> 3x^2 - 15x + 4x - 20 = 0
=> 3x(x - 5) + 4(x -5) = 0
=> (x - 5)(3x+4)=0
=> (x - 5) = 0 or (3x+4)= 0
=> x = 5 or x = - 4/3
ANSWERS : x = 5, - 4/3
Now LOOK here: 3 x 20 = 60 ; 60 = 15 x 4 & 15 - 4 = 11
so we have,
3x^2 - (15 - 4)x - 20 = 0
=> 3x^2 - 15x + 4x - 20 = 0
=> 3x(x - 5) + 4(x -5) = 0
=> (x - 5)(3x+4)=0
=> (x - 5) = 0 or (3x+4)= 0
=> x = 5 or x = - 4/3
ANSWERS : x = 5, - 4/3
2008-08-19 10:57 pm
4/3 or %=X
Try:
Looking at your other answers,
Find other questions on Y! Answers that is the same as this (resolved)
try mathkey.com
mathforum.org http://mathforum.org/library/drmath/sets/mid_algebra.html?s_keyid=15891082&f_keyid=15891105&start_at=481&num_to_see=40
Try Google. Hope I Helped!
Try:
Looking at your other answers,
Find other questions on Y! Answers that is the same as this (resolved)
try mathkey.com
mathforum.org http://mathforum.org/library/drmath/sets/mid_algebra.html?s_keyid=15891082&f_keyid=15891105&start_at=481&num_to_see=40
Try Google. Hope I Helped!
2008-08-19 10:56 pm
by factoring:
(3x + 4)(x - 5) = 0
so the values for x are -4/3 and 5.
(3x + 4)(x - 5) = 0
so the values for x are -4/3 and 5.
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