3x - 11 = x + 7
3x - x = 7 + 11
2x = 18
x = 9
Ta có: 3x-11=x+7
nên 2x=18
hay x=9
3x-11/11 - x/3 = 3x-5/7 - 5x-3/9
7)(16-8x)(2-6x)=0
8) (x+4)(6x-12)=0
9) (11-33x)(x+11)=0
10) (x-1/4)(x+5/6)=0
11) (7/8-2x)(3x+1/3)=0
12)3x-2x^2=0
(x+11).(7-3x)=0
Rút gọn các biểu thức
a( 3x-5) ( 2x+11)-(2x+3) (3x+7)
b (x-5) (2x+3)-2x(x-3)+x+7
Mọi người giúp tớ nhé , tớ đang gấp lắm.
3. Chứng minh rằng giá trị của các biểu thức sau không phụ thuộc vào x:
a/ A = 2x(x - 1) - x(2x + 1) - (3 - 3x)
b/ B = 2x(x - 3) - (2x - 2)(x - 2)
c/ C = (3x - 5)(2x + 11) - (2x + 3)(3x + 7)
d/ D = (2x + 11)(3x - 5) - (2x + 3)(3x + 7)
1) (4-3x) (10x-5)=0
2) (7-2x) (4+8x) = 0
3) (9-7x) (11-3x) = 0
4) (7-14x) (x-2) = 0
5) (2x+1) (x-3) = 0
6) (8-3x) (-3x+5) = 0
7) (16-8x) (2-6x) = 0
8) (x+4) (6x-12) = 0
9) (11-33x) (x+11) = 0
10) (x-1/4) (x+5/6) = 0
11) (7/8-2x) (3x+1/3) = 0
12) 3x - 2x^2 = 0
13) 5x + 10x^2 = 0
14) 4x + 3x^2 = 0
15) -8x^2 + x =0
16) 10x^2 - 15x = 0
17) x^2 -4 =0
18) 9 - x^2 = 0
19) x^2 -1 = 0
20) (x-3) (2x-1) = (2x-1) ( 2x+3)
21) (5+4x) (-x+2) = (5+4x) (7+5x)
22) (4+x) (x-5) = (3x-8) (x-5) = 0
23) (3x-8) (7-21x) - (9+2x) (7-21x)
24) (10+ 7x) (x+1) = (9x-2)(x-1)
25) (9x-4) (x-1/2) - (x-1/2) (6+x) = 0
26) 9x^2 - 1 = (3x-1) (x+4)
27) (x+7) (3x+1) = 49-x^2
28) (2x+1)^2 = (x-1)^2
29)x^3- 5x^2+6x = 0
30) 3x^2 + 5x + 2 = 0
Giảii giúpp mìnhh đyy mọii ngườii .
rút gọn A,B,C
A=(3x+7)(2x+3)-(3x-5)(2x+11)
B=(x2-2)(x2+x-1)-x(x3+x2-3x-2)
C=x(x3+x2-3x-2)-(x2-2)(x2+x-1)
1).(4-3x)(10-5x)=0 2).(7-2x)(4+8x)=0 3).(9-7x)(11-3x)=0
4).(7-14x)(x-2)=0 5).(\(\dfrac{7}{8}\)-2x)(3x+\(\dfrac{1}{3}\))=0 6).3x-2x\(^2\)
7).5x+10x\(^2\)
Cho A = (3x + 7)(2x + 3) – (3x – 5)(2x + 11); B = x(2x + 1) – x 2 (x + 2) + x 3 – x + 3. Chọn khẳng định đúng
A. A = B
B. A = 25B
C. A = 25B + 1
D. A = B 2
