9x+2=18x^2
2007-01-15 15:36:14 · 11 answers · asked by Just Wondering 5 in Science & Mathematics ➔ Mathematics
2/3 & -1/6
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Even though you don't need to use the quadratic formula to solve for x in this equation (it factors nicely), if the question requires you to use the quadratic formula, here's how:
The quadratic formula is [-b±√(b^2-4ac)] / (2a)
18x^2 = 9x + 2
18x^2 - 9x - 2 = 0
Therefore, a = 18, b = -9, c = -2
and you just plug those into the quadratic formula
[-(-9)±√((-9)^2-4(18)(-2))] / (2*18) =
[(9)±√(8-1/61+144)] / 36 =
[9±√225] / 36 =
[9±15] / 36 =
[24] / 36 & [-6] / 36 =
2/3 & -1/6
2007-01-15 15:39:08 · answer #1 · answered by Anonymous · 0⤊ 0⤋
properly the formulation for fixing an quadratic equation is -b + - the sq. root of b squared + 4 x A rewrite the equation like this 8x + x -5 8x=A x=b and -5 is c -x + and minus x to the 2d potential + 4 x 8 x -5 be squared equals 8x8 it is sixty 4 + 4 x a x -5 a advantageous 20 x X 20 x a million is 20 the sq. root of 20 is 4.40 seven + -8 = -3.fifty 3 then minus is is 11.fifty 3 so which you have 2 solutions 11.fifty 3 advantageous and -3.fifty 3 destructive huge sort thats how i do quadratic equations I dont be attentive to if its spectacular it is fairly useful to verify with somebody who's acquainted with greater on the subject of the stuff like a math instructor
2016-10-31 05:41:48 · answer #2 · answered by ? 4 · 0⤊ 0⤋
Rearrange: 18x^2-9x-2=0
Now use formula with a=18, b=-9, c=-2:
x=[9 +- sqrt(81 + 4*18*2)]/(2*18)
x= (9 +- sqrt 225)/36
x= (9 +- 15)/36
x= 24/36 or x = -6/36
So x=2/3 or x = -1/6
2007-01-15 15:45:09 · answer #3 · answered by martina_ie 3 · 0⤊ 0⤋
18x^2 - 9x - 2 = 0
(3x - 2)(6x + 1) = 18x^2 -12x + 6x - 2
= 18x^2 - 9x - 2
3x - 2 = 0 or 6x + 1 = 0
x = 2/3 or x = -1/6
I don't like to use the quadratic formula unless necessary.
2007-01-15 15:43:49 · answer #4 · answered by Anonymous · 0⤊ 1⤋
18x^2 -9x -2 = 0
(6x +1)(3x -2) = 0
x = -1/6, x = 2/3
2007-01-15 15:44:24 · answer #5 · answered by John T 6 · 0⤊ 1⤋
Subtract 18x^2 to get something of the form ax^2 + bx + c.
The quadratic formula is [-b +/- sqrt(b^2 - 4ac)]/(2a), where the b^2 - 4ac is called the discriminant, if that helps you remember the formula.
2007-01-15 15:40:01 · answer #6 · answered by Anonymous · 0⤊ 1⤋
2/3 or -1/6
2007-01-15 15:40:38 · answer #7 · answered by Roxanne 3 · 0⤊ 1⤋
2/3 & -1/6
2007-01-15 15:43:37 · answer #8 · answered by Anonymous · 0⤊ 1⤋
18x²-9x-2=0
x=2/3 or x=-0.1666666666
2007-01-15 15:41:02 · answer #9 · answered by A 150 Days Of Flood 4 · 0⤊ 1⤋
nope, not with quadratic, use synthetic division or trig functions.
2007-01-15 15:39:47 · answer #10 · answered by ronny 2 · 0⤊ 2⤋