GIẢI CỎC PHƯƠNG TRỠNH TỚCH SAU
Bài 4: Giải cỏc phương trỡnh tớch sau:
a. (x - 1)(5x + 3) = (3x - 8)(x - 1)
b. 3x(25x + 15) - 35(5x + 3) = 0
c. (2 - 3x)(x + 11) = (3x - 2)(2 - 5x)
d. (2x
2
+ 1)(4x - 3) = (2x
2
+ 1)(x - 12)
e. (2x + 1)
2
+ (2 - x)(2x - 1) = 0
f. (x + 2)(3 - 4x) = x
2
+ 4x + 4
Giải: a. (x - 1)(5x + 3) = (3x - 8)(x - 1)
(x - 1)(5x + 3) - (3x - 8)(x - 1) = 0
(x - 1)(5x + 3 - 3x + 8) = 0
11(x - 1)(2x + 11) = 0
x = 1 hoặc x = -
2,1 11 2Vậy S =
15x(5x + 3) - 35(5x + 3) = 0
(5x + 3)(15x - 35) = 0
73hoặc x =
x = -
53;7 3(2 - 3x)(x + 11) + (2 - 3x)(2 - 5x) = 0
2 - 3x)(x + 11 + 2 - 5x) = 0
(2 - 3x)(- 4x + 13) = 0
2hoặc x =
13x =
4;13(2x
2
+ 1)(4x - 3) - (2x
2
+ 1)(x - 12) = 0
(2x
2
+ 1)(4x - 3 - x + 12) = 0
(2x
2
+ 1)(3x + 9) = 0
x = - 3
Vậy S =
3(2x - 1)(2x - 1 + 2 - x) = 0
(2x - 1)(x + 1) = 0
1hoặc x = - 1
1 ; 1(x + 2)(3 - 4x) - (x + 2)
2