更新1:
please help!!!!
x=square root of 4x+12?
回答 (6)
2009-06-04 2:57 pm
✔ 最佳答案
x = √(4x+12)Square both sides of the above equation, then we get
x^2 = 4x+12
x^2-4x-12 = (4x+12)-4x-12
x^2-4x-12 = 4x-4x+12-12
x^2-4x-12 = 0
x^2+2x-6x-12 = 0
x(x+2)-6(x+2) = 0
(x+2)(x-6) = 0
x = -2 or x=6
Hope this helps.
2009-06-04 10:06 pm
(x)^2=(â(4x+12))^2
x^2=4x+12
x^2-4x-12=0
(x+2)(x-6)=0
x+2=0 x-6=0
x=-2 x=6
x={-2,6} answer//
x^2=4x+12
x^2-4x-12=0
(x+2)(x-6)=0
x+2=0 x-6=0
x=-2 x=6
x={-2,6} answer//
2009-06-04 10:04 pm
x = â(4x + 12)
x² = (â(4x + 12))²
x² = 4x + 12
x² - 4x - 12 = 0
find the factor of -12
(-1)(12), (-2)(6), (-3)(4), (-4)(3), (-6)(2), (-12)(1)
use (-6)(2) because -6 + 2 = -4 (the coeffisient of x)
x² - 4x - 12 = 0
(x - 6)(x + 2) = 0
x = 6 or x = -2
x² = (â(4x + 12))²
x² = 4x + 12
x² - 4x - 12 = 0
find the factor of -12
(-1)(12), (-2)(6), (-3)(4), (-4)(3), (-6)(2), (-12)(1)
use (-6)(2) because -6 + 2 = -4 (the coeffisient of x)
x² - 4x - 12 = 0
(x - 6)(x + 2) = 0
x = 6 or x = -2
2009-06-04 10:00 pm
x = â(4x+12) so x>=0
x² = [â(4x+12)]² where x >= 0
x² = 4x + 12 where x >= 0
x² - 4x - 12 = 0 where x >= 0
(x-6)(x+2) = 0 where x >= 0
x = 6 only valid answer
Gosh, I love thumbs down for the only correct answer, plug in x = -2 and see why it's wrong...
-2 = â(4*-2+12)
-2 = â4
-2 â 2
x = -2 is what we call an extraneous solution
x² = [â(4x+12)]² where x >= 0
x² = 4x + 12 where x >= 0
x² - 4x - 12 = 0 where x >= 0
(x-6)(x+2) = 0 where x >= 0
x = 6 only valid answer
Gosh, I love thumbs down for the only correct answer, plug in x = -2 and see why it's wrong...
-2 = â(4*-2+12)
-2 = â4
-2 â 2
x = -2 is what we call an extraneous solution
2009-06-04 9:58 pm
x= -2 and 6
2009-06-05 7:43 pm
x = â(4x + 12)
x^2 = 4x + 12
x^2 - 4x - 12 = 0
x^2 + 2x - 6x - 12 = 0
(x^2 + 2x) - (6x + 12) = 0
x(x + 2) - 6(x + 2) = 0
(x + 2)(x - 6) = 0
x + 2 = 0
x = -2
x - 6 = 0
x = 6
(-2 cannot be the answer because â4 â -2)
â´ x ONLY equals 6.
x^2 = 4x + 12
x^2 - 4x - 12 = 0
x^2 + 2x - 6x - 12 = 0
(x^2 + 2x) - (6x + 12) = 0
x(x + 2) - 6(x + 2) = 0
(x + 2)(x - 6) = 0
x + 2 = 0
x = -2
x - 6 = 0
x = 6
(-2 cannot be the answer because â4 â -2)
â´ x ONLY equals 6.
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