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Please show me the method and fomula...

2007-01-13 15:01:14 · 6 answers · asked by Intrexpo 1 in Science & Mathematics Mathematics

6 answers

(x^2-2x)^2+3(x^2-2x)-4=0?

Probably easiest to replace x^2 - 2x with u to get

u^2 + 3u - 4 = 0

(u+4)(u-1) = 0

u = -4 or u = 1

Then put back the x^2 - 2x for u and solve those simpler equations

2007-01-13 15:06:28 · answer #1 · answered by hayharbr 7 · 0 0

I assume the problem reads like this because you're missing a parenthesis:
(x^2 - 2x)^2 + 3(x^2 - 2x) - 4 = 0, solve for x
Try substitution
m = x^2 - 2x
So
m^2 + 3m - 4 = 0
(m + 4)(m - 1) = 0
So either m + 4 = 0, or m - 1 = 0
m = -4, 1
If m = -4, then
x^2 - 2x = -4
x^2 - 2x + 4 = 0
referring to the quadratic equation, since b^2 - 4ac = 4 - 16 = -12 < 0, there is no real solution for m = -4. (We would have to take the square root of -12 to do so.) We disregard this possibility.
Now try m = 1
x^2 - 2x = 1
x^2 - 2x - 1 = 0
again using the quadratic equation,
x = 1 +/- sqrt(2)

Hope this helps.

2007-01-14 01:38:50 · answer #2 · answered by Draco Moonbeam 3 · 0 0

i know 3+1=4

2007-01-14 12:22:51 · answer #3 · answered by jessica_elenita 2 · 0 0

((x^2-2x)^2+3x^2-2x)-4 = 0
x^4-4x^3+4x^2+3x^2-2x-4 = 0
x^4 - 4x^3 + 7x^2 - 2x - 4 = 0

2007-01-13 23:05:09 · answer #4 · answered by JasonM 7 · 1 0

You are missing(or have too many) parentheses?? Very important in math.

2007-01-13 23:06:01 · answer #5 · answered by hello 6 · 0 1

14528

2007-01-13 23:04:26 · answer #6 · answered by twixlicker 3 · 0 1

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