`(2x+3)^2 . (x+1)^2`
`=[(2x)^2 +2.2x.3+3^2].(x^2 +2.x.1+1^2)`
`=(4x^2 +12x+9).(x^2 +2x+1)`
`=4x^4 + 8x^3 +4x^2 +12x^3 +24x^2 +12x+9x^2 + 18x+1`
`=4x^4 +20x^3 +27x^2 +30x+1`
Bài I. Rút gọn các biểu thức sau:
a) 3x(2x+1)+ (2x - 3)(x+1),
b) x(3x - 2)2 + 3(x-2)(x+2)
c) (2x+1)(4x² - 2x+1)-2x(2x+3)(2x - 3)-(x-3)²
Tìm x biết:
a)(x+3)^2+(x-2)(x+2)-2(x+1)=7
b)x(2x-1)-(x-2)(2x+3)=0
c)(x-1)(x+2)-x-2=0
d)x[(3x+2)+(x+1)^2-(2x-5)(2x+5)]=0
đ) 2x^2-7x+5=0
e) (2x+3)(x-5)=(2x+1)(2×+3)
1. Thu gọn:
a) (3x-1). (x-2) + (x-1). (x+1)
b) (4x-3). (2x-5) - (8x-2). (x-1)
2. Tìm x:
a) 3x. (x-3) - x. (3x-2) = 2
b) -2x. (x+1) - 3. (1-x) + 2x2 = 3
c) (x-2). (x+2) + (3.x). (x+1) = 0
d) (2x-1). (x+3)- (x-2). (2x+1) = 10
3A. Rút gọn các biểu thức sau: a) 5x ^ 2 * (3x ^ 2 - 1) - 6x(4x ^ 3 - 3x + 1) - 2x ^ 3 * (3x - 1) b) 1/2 * x(x ^ 2 - 2/5 * x + 2) - 3/4 * x ^ 2 * (x + 1/3) - x(x + 1) c) 1 1/2 * x ^ 2 * (x ^ 2 - 2x) - 2x(x ^ 3 + x ^ 2 + 1) + 2(x - 1) d) x(x ^ 3 - 2x ^ 2) + 5x(x ^ 2 - 2x + 1/2) - x ^ 2 * (x ^ 2 - x + 1) . Rút gọn các biểu thức sau: 3B a) 3x(- x ^ 2 - 5) + 5x(x ^ 3 + 7) - 3x ^ 2 * (x ^ 2 - x + 5) + 2(4 - x) ; b) 25x - 4(3x - 1) + 7x(5 - 2x ^ 2) ; c) 4x(x ^ 3 - 4x ^ 2) + 2x(2x ^ 3 - 3x ^ 2 + 7x + 1) ; d) - 4/2 * x ^ 2 * (3x ^ 2 - 6x + 9) + 8x(x ^ 3 - 3x ^ 2 + 2x - 1) - x(x ^ 2 - 2x) 4A. Rút gọn các biểu thức sau: a) (4x - 1)(3x + 2) - 5x(x - 3) ; b) (5x - 2)(x + 1) - 2x(x ^ 2 + x - 3) ; c) (x + 1)(2x - 1) + x(x ^ 2 - x + 1) ; d) (3x ^ 2 + x + 2) * 0.3 - (2x + 1) * 0.2(3 + x) .
Bài 1: Rút gọn các biểu thức sau:
a, A = (x-2).(2x-1) - 2x (x+3)
b, B = (3x-2).(2x+1) - (6x-1).(x+2)
c, C = 6x.(2x+3) - (4x-1).(3x-2)
d, D = (2x+3).(5x-2)+(x+4).(2x-1) - 6x.(2x-3)
Bài 2: Chứng tỏ rằng các đa thức không phụ thuộc vào biến.
a, 2x(3x-5).(x+11) - 3x.(2x+3).(x+7)
b, (x2+5x-6).(x-1) - (x+2).(x2-x+1) - x(3x-10)
c, (x2+x+1).(x-1) - x2(x+1) + x2 - 5
1. Thu gọn:
a) 5x. (x-3) - x. (5x+1)
b) -3x. (x-1) - x. (x+1) + 4x. (x-2)
c) (3x-1). (x-2) + (x-1). (x+1)
d) (4x-3). (2x-5) - (8x-2). (x-1)
2. Tìm x:
a) 3x. (x-3) - x. (3x-2) = 2
b) -2x. (x+1) - 3. (1-x) + 2x2
c) (x-2). (x+2) + (3.x). (x+1) = 0
d) (2x-1). (x+3)- (x-2). (2x+1) = 10
Tìm x,biết:
a) 3(2x-1) -5(x-3) +6(3x-4) = 24
b) 2x2 + 3(x2 -1) = 5x (x+1)
c) 2x(5-3x) + 2x(3x-5) -3(x-7) = 3
d) 3x(x+1) -2x(x+2) = -1-x
e) 3x(x-2) -x(1+3x) = 14
f) 2x(x+3) -3(x2 + 1) = x+1 -x(x-2)
giúp mik nha !!!! :D
Bài 1 : Rút gọn
A= 3(x-1)2-(x+1)2+2(x-3)(x+3)-(2x+3)2-(5-20x)
B= 5x(x-7)(x+7)-x(2x-1)2-(x3+4x2-246x)-175
C= -2x(3x+2)2+(4x+1)2+2(x3+8x+3x-2)-(5-x)
D= (5x-2)2-(6x+1)2+11(x-2)(x+2)-16(3-2x)
E= 4x(x+3)-(x-5)2-3(x+1)2+(2x+2)2-(4x+5)
F= (2x-3)(x+2)(x-2)-2(x+3)-(x+4)3+(x-3)(x2+3x+9)+9x2+110x
tìm x:
a)2x^2+3(x^2-1)=5x(x+1)
b)2x(5-3x)+2x(3x-5)-3(x-7)=3
c)3x(x+1)-2x(x+2)=-1-x
