Cac BT giai phuong trinh toan 8

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Chuyên đề : Giải phơng trình (LớP 8) Bài : Giải các phương trỡnh bậc sau

a) 2x +1 = 15-5x b/ 3x – = 2x + c) 7(x - 2) = 5(3x + 1) d/ 2x + = 20 – 3x e/- 4x + = f/ x – = 18 - 5x g/ x(2x – 1) = h/ 3x – = x + i/ 5x −2 4=16x+1

7 j/ 2(x +1) = 5x - k) 2x + = l) 2x+1

6 −

x −2

4 =

3−2x

3 − x m) 2x - = n) 4x + 20 = o/ + 2x −6 = 3− x4 p) 15 - 7x = - 3x q)

2

x

+ x =

x

r)

1 2

x x 

r)

2

(x - 2) (x + 1) (x - 4)(x - 6)

- =

12 21 28 t)

3(2x +1) 3x + 2(3x - 1)

- - =

4 10

u)

3(2x +1) 5x + x +

- + = x +

4 12 v)

x + x + x + x +

+ = +

2009 2007 2005 1993

x)

392 - x 390 - x 388 - x 386 - x 384 - x

+ + + + = -5

32 34 36 38 40 y)

x - 15 x - 23

+ - =

23 15

Bi : Giải các phng trỡnh sau (đa PT dạng pt bậc PT tÝch) a) y(y2-1) = y2 - 5y + = b) y( y -

2 )( 2y + ) = c) 4y2 +1= 4y d) y2 – 2y = 80

g) (2y – 1)2 – (y + 3)2 = 0 h) 2y211y = i) (2y - 3)(y +1)+ y(y - 2) = 3(y +2)2 j) (y

❑2 - 2y + 1) – =

k) y2 + 5y + = l) y2 + 7y + = 0 m) y2 – y – 12 = n) x2 + 2x + =

o) y3 – y2 – 21y + 45 = p) 2y3 – 5y2 + 8y – = 0 q) (y+3)2 + (y + )2 =

Bài Giải các phương trình cã chøa dÊu GTT§ sau

a) x 1 b) x 2x c) |x −3|=x −1 d)

1

4 5( 2)

2x  x  x e) ¿5x −5∨¿0 f) x 3

g) |x+5| = 3x - h) x 3 2x 2x i) |x −3|=x −1 j) 2x – 0,5  - = k) 2x +  = x - 1 l)  – x  = 3x +

m) (x + 1)2 = x –  n) 11x -  = 32x - 5 Bi 4Giải các phng trỡnh có chøa Èn ë mÉusau:

a) x −x −32+x+2

x =2 b/ ( x – ) (

2

3 x – ) = c /

x −3

x −2+

x+2

x =2

d) x+1x −2x −x −13=2x+3

x2−1 f/

x −1

x + x −2

x+1=2 g)

1

x x

x x



 

h) xx+3+1+x −2

x = i)

2

x+1−

x −1=5 j)

2x + 2x -1

- =

2x -1 2x +1 4x -1 k)

3x −1

x −1 − 2x+5

x −3 =1 l)

x+1−

x −2=

3x −11

(x+1)(x −2)

m)

3x -1 2x +

- + =

x - x + x + 2x - n)

x+2

x −2−

x=

2

x(x −2) o) x −x+22+¿

3

x −2=

x2−11

x2−4 p)

2

x x 2x x x x



 

  

p) 2x

x −1+

x2+2x −3= 2x −5

x+3 q) x

− x x+3 −

x2 x −3=

7x2−3x

9− x2

r)

1

+ = + x

x - x -1 s)

2

= x + 4x - 21 x -

t) 2

1

+ =

x + 2x + x +1 u)

2x

2x −1+

x

2x+1=1+

4 (2x −1) (2x+1) Bài 5 : Giải bin lun các phơng trình sau sau(x ẩn, m lµ tham sè)

a) 7( m - 11)x - 2x + = 5m b) 2mx + 4( 2m + ) = m2 + ( x – 1)

3)

2

2

mx + m -1 x +

+ = + (x + m + 1)

6 10 4)

x - a x - b

+ =