i ended up with some wierd answer. For both X's i got
x=-3 and x=-3 why are both of my X's the same answer???
2007-04-25 17:24:46 · 12 answers · asked by andrew 3 in Science & Mathematics ➔ Mathematics
If that is your answer is just means that the parabola that this equation represents just touches the x-axis at x=-3 but does not cross it--nothing strange about double roots.
2007-04-25 17:27:23 · answer #1 · answered by bruinfan 7 · 0⤊ 0⤋
Your answer is perfectly normal. There are many quadratics that have what are called "double roots" or "repeated roots". Do not panic, as they appear all the time. Graphically speaking, the quadratic parabola only "touches" the horizontal axis instead of crossing it. Analytically speaking, the determinant of the quadratic is zero, resulting in a single value in the numerator of the quadratic formula.
Also observe the equation is a "perfect square".
2x^2+12x+10= -8 -> 2x^2+12x+18= 0 -> x^2+6x+9=0 -> (x+3)(x+3) = 0.
Yielding the double root.
Cheers and hope this helps your understanding of quadratics.
2007-04-26 00:31:16 · answer #2 · answered by vokuheila 2 · 0⤊ 0⤋
2x^2 + 12x + 10 = -8
2x^2 + 12x + 10 + 8 = 0
2x^2 + 12x + 18 = 0
x^2 + 6x + 9 = 0
(x + 3)^2 = 0
therefore x = -3
2007-04-26 00:32:52 · answer #3 · answered by aquarian8502 2 · 0⤊ 0⤋
2x^2 + 12x + 10 = -8
2x^2 + 12x + 10 + 8 = 0
2x^2 + 12x + 18 = 0
2(x^2 + 6x + 9) = 0
2(x+3)(x+3)= 0
Answer is only one x=-3...no worries. But must remember that before doing factorisation, u should take out the common factors 1st.
2007-04-26 00:32:31 · answer #4 · answered by QiQi 3 · 0⤊ 0⤋
That equation is non linier equation, its called parabolic equation.
It's could be right if you have 2 value of x. Because if you make on cartesian drawing, with x as horizontal line and y as vertikal line. Then right side of the cross section on x line is positive value and the opposite is negative. Also the upper section of cross section on y line is positive while opposite is negative.(What I mean for cross section is when vertical and horizontal line (y & x) meet.)
If you draw the result of those equation, the line will return if its allready get its maximum or minimum value, and its shape like open parabola.
But I thing you do that equation in the wrong way. Let me try to solve it,
2x^2 + 12x + 10 = -8
equal to : x^2 + 6x + 5 = -4 (each side divided by 2)
equal to : x^2 + 6x + 9 = 0 (move -4 to left side)
equal to : (x + 3) (x + 3) =0
so you'll get the result as -3
Cheers... hope you'll understand
2007-04-26 03:54:46 · answer #5 · answered by wahyu 3 · 0⤊ 0⤋
2x^2+12x+10+8=0 (devide both sides by 2)
x^2+6x+9=0
(x+3)(x+3)=0
x+3=0 x+3=0
x=-3 x=-3
your answers are correct
2007-04-26 00:35:50 · answer #6 · answered by Alandi 3 · 0⤊ 0⤋
both of the roots are the same.
It happens when it is a complete square.
2x^2 + 12X + 18 = 0
x^2 +6x + 9 = 0
(x+3)(x+3) = 0
X = -3
it is the complete square (x+3)^2 = 0
2007-04-26 00:32:23 · answer #7 · answered by modern wushu 2 · 0⤊ 0⤋
2x^2 + 12x + 18
(2x +6) (x + 3)
x= -3 and x = -3
gee i get the same thing
2007-04-26 00:28:32 · answer #8 · answered by msmthtchr 3 · 1⤊ 0⤋
2x^2+12x+10=-8
2x^2+12x+10+8=0
2x^2+12x+18=0
2(x^2+6x+9)=0
2(x+3)(x+3)=0
x=-3, x=-3
and yes are correct.
2007-04-26 00:43:56 · answer #9 · answered by bootis32 6 · 0⤊ 0⤋
your answer is just x = - 3
it doesn't matter that both of them are the same because if you plug x = - 3 back into your original equation, it equals - 8: both sides are - 8.
2007-04-26 00:31:04 · answer #10 · answered by Nikki 2 · 0⤊ 0⤋