2007-06-23 21:45:45 · 11 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
x=4
x= -10/3
2007-06-23 21:49:59 · answer #1 · answered by MDA 4 · 0⤊ 0⤋
Given 9x² - 6x - 120 = 0 , first simplify ,
so that 3x² - 2x - 40 = 0 and , by observation ,
( 3x + 10 ) ( x - 4 ) = 0 , x = { -10/3 , 4 } .
2007-06-24 05:10:13 · answer #2 · answered by Zax 3 · 0⤊ 0⤋
9x^2 - 6x - 120 = 0
(3x -1)^2 = 121
3x - 1 = 11 or 3x - 1 = -11
x = 4 or x = -10/3
2007-06-24 08:26:19 · answer #3 · answered by handsomeboy1702 2 · 0⤊ 0⤋
9x^2 - 6x - 120 = 0
=> 9x^2 + 30x - 36 x - 120 = 0
= > (9x^2 + 30x) - (36x - 120) = 0
=> 3x(3x + 10) - 12(3x + 10) = 0
=> (3x + 10) (3x - 12) = 0
=> 3 (3x + 10 ) (x - 4 ) = 0
=> (3x + 10 ) ( x - 4) = 0
answer.......... x = +4 or x = -10/3
2007-06-24 07:12:59 · answer #4 · answered by jack 1 · 1⤊ 0⤋
its so easy
9x^2-6x-120=0 ..........dividing by 3
=3x^2-2x-40=0
solving this quadratic eq^n you will get-
3x(x-4)-10(x-4)=0
( 3x-10)(x-4)=0
3x-10=0 or x-4=0
x=10/3 x=4
2007-06-24 05:17:29 · answer #5 · answered by sneha 2 · 0⤊ 0⤋
3x² - 2x - 40 = 0
x = [ 2 ± â(4 + 480) ] / 6
x = [ 2 ± â484 ] / 6
x = [ 2 ± 22 ] / 6
x = 24 / 6 , x = - 20 / 6
x = 4 , x = - 10/3
2007-06-24 05:17:37 · answer #6 · answered by Como 7 · 0⤊ 0⤋
Dividing by 3 we get
3x^2-2x-40=0.....now factorise
(3x+10)(x-4)=0
x=-10/3 or 4.
2007-06-24 04:52:41 · answer #7 · answered by Anonymous · 0⤊ 0⤋
3x^2 - 2x - 40 = 0
(x - 4)(3x + 10) = 0
x - 4 = 0
x = 4
3x + 10 = 0
3x = -10
x = -10/3
4 and -10/3 are your answers
2007-06-24 05:15:07 · answer #8 · answered by Becky M 4 · 0⤊ 0⤋
3x^2 - 2x - 40 = 0
( x - 6 ) ( 3x + 10 ) = 0
x = 6, -10/3
2007-06-24 04:53:13 · answer #9 · answered by teokz2002 1 · 0⤊ 2⤋
i think there are two answers for x so it's 4 and -3.333
2007-06-24 04:51:08 · answer #10 · answered by Curious Casey 2 · 0⤊ 0⤋