Question

Đã trả lời bởi chuyên gia

Answer 1

a.

$2 x - 12 = 5 x + 21 2 x - 5 x = 21 + 12 - 3 x = 33 x = - 11$

b.

$7 x - 5 = 13 - 5 x 7 x + 5 x = 13 + 5 12 x = 18 x = \frac{3}{2}$

c.

$10 x - 3 + 5 x = 4 x + 12 10 x + 5 x - 4 x = 12 + 3 11 x = 15 x = \frac{15}{11}$

d.

$8 (3 x - 2) - 14 x = 2 (4 - 7 x) + 15 24 x - 16 - 14 x = 8 - 14 x + 15 24 x - 14 x + 14 x = 8 + 15 + 16 24 x = 39 x = \frac{13}{8}$

e.

$12 - 3 {(x - 2)}^{2} = (x + 2) (1 - 3 x) + 2 x 12 - 3 (x^{2} - 4 x + 4) = x - 3 x^{2} + 2 - 6 x + 2 x 12 - 3 x^{2} + 12 x - 12 = - 3 x - 3 x^{2} + 2 15 x = 2 x = \frac{2}{5}$

g.

$x {(x - 3)}^{2} - 3 x = {(x + 2)}^{3} + 1 x (x^{2} - 6 x + 9) - 3 x = x^{3} + 6 x^{2} + 12 x + 8 + 1 x^{3} - 6 x^{2} + 9 x - 3 x = x^{3} + 6 x^{2} + 12 x + 8 + 1 - 12 x^{2} - 6 x - 9 = 0 4 x^{2} + 2 x + 3 = 0 (v ô n g h i ệ m)$

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Answer 2

a.

$2 x - 12 = 5 x + 21 2 x - 5 x = 21 + 12 - 3 x = 33 x = - 11$

b.

$7 x - 5 = 13 - 5 x 7 x + 5 x = 13 + 5 12 x = 18 x = \frac{3}{2}$

c.

$10 x - 3 + 5 x = 4 x + 12 10 x + 5 x - 4 x = 12 + 3 11 x = 15 x = \frac{15}{11}$

d.

$8 (3 x - 2) - 14 x = 2 (4 - 7 x) + 15 24 x - 16 - 14 x = 8 - 14 x + 15 24 x - 14 x + 14 x = 8 + 15 + 16 24 x = 39 x = \frac{13}{8}$

e.

$12 - 3 {(x - 2)}^{2} = (x + 2) (1 - 3 x) + 2 x 12 - 3 (x^{2} - 4 x + 4) = x - 3 x^{2} + 2 - 6 x + 2 x 12 - 3 x^{2} + 12 x - 12 = - 3 x - 3 x^{2} + 2 15 x = 2 x = \frac{2}{5}$

g.

$x {(x - 3)}^{2} - 3 x = {(x + 2)}^{3} + 1 x (x^{2} - 6 x + 9) - 3 x = x^{3} + 6 x^{2} + 12 x + 8 + 1 x^{3} - 6 x^{2} + 9 x - 3 x = x^{3} + 6 x^{2} + 12 x + 8 + 1 - 12 x^{2} - 6 x - 9 = 0 4 x^{2} + 2 x + 3 = 0 (v ô n g h i ệ m)$

Answer 3

a 2x-12=5x+21

=> 2x - 5x = 21 + 12

=> -3x = 33

=> x = 33 : (-3)

=> x = -11

b. 7x-5=13-5x

=> 7x + 5x = 13 + 5

=> 12x = 18

=> x = 18 : 12

=> x =

\frac{3}{2}

c. 10x-3+5x=4x+12

=> 15x - 4x = 12 + 3

=> 11x = 15

= > x = \frac{15}{11}

d. 8(3x-2)-14x=2(4-7x)+15x

=> 24x - 16 - 14x = 8 - 14x +15x

=> 10x - 16 = 8 + x

=> 10x - x = 8 + 16

=> 9x = 24

=> x =

\frac{8}{3}

e . 12 - 3 {(x - 2)}^{2} = (x + 2) (1 - 3 x) + 2 x = > 12 - 3 (x^{2} - 4 x + 4) = x - 3 x^{2} + 2 - 6 x + 2 x = > 12 - 3 x^{2} + 12 x - 12 = - 3 x^{2} - 3 x + 2 = > 12 x + 3 x = 2 - 12 + 12 = > 15 x = 2 = > x = \frac{2}{15}

g. x(x-3)2-3x=(x+2)3+1 =>x.[(x-3)2-3]=x3+6x2+12x+8+1=>x.(x2-6x+9-3)=x3+6x2+12x+9=>x3-6x2+6x=x3+6x2+12x+9=>-12x2-6x-9=0 ( vô nghiệm)=> phương trình vô niệm

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Answer 4

a 2x-12=5x+21

=> 2x - 5x = 21 + 12

=> -3x = 33

=> x = 33 : (-3)

=> x = -11

b. 7x-5=13-5x

=> 7x + 5x = 13 + 5

=> 12x = 18

=> x = 18 : 12

=> x =

\frac{3}{2}

c. 10x-3+5x=4x+12

=> 15x - 4x = 12 + 3

=> 11x = 15

= > x = \frac{15}{11}

d. 8(3x-2)-14x=2(4-7x)+15x

=> 24x - 16 - 14x = 8 - 14x +15x

=> 10x - 16 = 8 + x

=> 10x - x = 8 + 16

=> 9x = 24

=> x =

\frac{8}{3}

e . 12 - 3 {(x - 2)}^{2} = (x + 2) (1 - 3 x) + 2 x = > 12 - 3 (x^{2} - 4 x + 4) = x - 3 x^{2} + 2 - 6 x + 2 x = > 12 - 3 x^{2} + 12 x - 12 = - 3 x^{2} - 3 x + 2 = > 12 x + 3 x = 2 - 12 + 12 = > 15 x = 2 = > x = \frac{2}{15}

g. x(x-3)2-3x=(x+2)3+1 =>x.[(x-3)2-3]=x3+6x2+12x+8+1=>x.(x2-6x+9-3)=x3+6x2+12x+9=>x3-6x2+6x=x3+6x2+12x+9=>-12x2-6x-9=0 ( vô nghiệm)=> phương trình vô niệm

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