Question

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Answer 1

$b, {(x - 1)}^{3} - (2 - x) (4 + 2 x + x^{2}) + 3 x . (x + 2) = 17 < = > x^{3} - 3 x^{2} + 3 x - 1 - 8 + x^{3} + 3 x^{2} + 6 x - 17 = 0 < = > 2 x^{3} + 9 x - 26 = 0 < = > x \approx 1, 7328 (n g h i ệ m x ấ u) V ậ y x \approx 1, 7328 c, (x + 3) (x^{2} - 3 x + 9) - x^{3} = 2 x < = > x^{3} + 27 - x^{3} = 2 x < = > 2 x = 27 < = > x = \frac{27}{2} V ậ y x = \frac{27}{2} d, {(x + 2)}^{2} + {(x - 3)}^{2} - 2 . (x - 1) (x + 1) = 9 < = > x^{2} + 4 x + 4 + x^{2} - 6 x + 9 - 2 . (x^{2} - 1) = 9 < = > 2 x^{2} - 2 x + 13 - 2 x^{2} + 2 = 9 < = > - 2 x + 15 = 9 < = > - 2 x = - 6 < = > x = 3 V ậ y x = 3$

$e, {(x - 2)}^{3} - (x - 3) (x^{2} + 3 x + 9) + 6 {(x + 1)}^{2} = 15 < = > x^{3} - 6 x^{2} + 12 x - 8 - x^{3} + 27 + 6 x^{2} + 12 x + 6 = 15 < = > 24 x + 25 = 15 < = > 24 x = - 10 < = > x = \frac{- 5}{12} V ậ y x = \frac{- 5}{12}$ .

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Answer 2

$b, {(x - 1)}^{3} - (2 - x) (4 + 2 x + x^{2}) + 3 x . (x + 2) = 17 < = > x^{3} - 3 x^{2} + 3 x - 1 - 8 + x^{3} + 3 x^{2} + 6 x - 17 = 0 < = > 2 x^{3} + 9 x - 26 = 0 < = > x \approx 1, 7328 (n g h i ệ m x ấ u) V ậ y x \approx 1, 7328 c, (x + 3) (x^{2} - 3 x + 9) - x^{3} = 2 x < = > x^{3} + 27 - x^{3} = 2 x < = > 2 x = 27 < = > x = \frac{27}{2} V ậ y x = \frac{27}{2} d, {(x + 2)}^{2} + {(x - 3)}^{2} - 2 . (x - 1) (x + 1) = 9 < = > x^{2} + 4 x + 4 + x^{2} - 6 x + 9 - 2 . (x^{2} - 1) = 9 < = > 2 x^{2} - 2 x + 13 - 2 x^{2} + 2 = 9 < = > - 2 x + 15 = 9 < = > - 2 x = - 6 < = > x = 3 V ậ y x = 3$

$e, {(x - 2)}^{3} - (x - 3) (x^{2} + 3 x + 9) + 6 {(x + 1)}^{2} = 15 < = > x^{3} - 6 x^{2} + 12 x - 8 - x^{3} + 27 + 6 x^{2} + 12 x + 6 = 15 < = > 24 x + 25 = 15 < = > 24 x = - 10 < = > x = \frac{- 5}{12} V ậ y x = \frac{- 5}{12}$ .

Answer 3

b, (x−1)3−(2−x)(4+2x+x2)+3x.(x+2)=17<=>x3−3x2+3x−1−8+x3+3x2+6x−17=0<=>2x3+9x−26=0<=>x≈1,7328 (nghiệm xấu)Vậy x≈1,7328c, (x+3)(x2−3x+9)−x3=2x<=>x3+27−x3=2x<=>2x=27<=>x=272Vậy x=272d, (x+2)2+(x−3)2−2.(x−1)(x+1)=9<=>x2+4x+4+x2−6x+9−2.(x2−1)=9<=>2x2−2x+13−2x2+2=9<=>−2x+15=9<=>−2x=−6<=>x=3

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