\(B=x^3-3x^2+3x-1-x^3+8-3\left(x^2-16\right)\)
\(=-3x^2+3x+7-3x^2+48\)
=3x+55
=-6+55=49
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Bài 3: Những hằng đẳng thức đáng nhớ
Các câu hỏi tương tự
Tìm x: a)(2x+1)(1-2x)+(1-2x)^2=18
b) 2(x+1)^2-(x-3)(x+3)-(x-4)^2=0
c) (x-5)^2-x(x-4)=9
d) (x-5)^2+(x-4)(1-x)=0
1, tìm x :
a) (x+2).(x+3)-(x-2).(x+5)=0
b) (2x+3).(x-4)+(x-5).(x-2)=(x-4).(3x-5)
c) (3x-5).(7-5x)-(5x+2).(2-3x)=3
d)(x-7).(x+7)-(x-4)2-x=10+3
e) (x+1/2)2-(x-1).(x+1)=2x-1
2, Thu gọn :
a) (x+5)2-(3-x)2-2(x-4).(x+4)
b)4(x-1)2+(2x+3)2-8(x-2)(x+2)
tìm x biết:
a) (x-3)2-4=0
b) x2-2x=24
c) (x+4)2-(x+1)(x-1)=16
d) (2x+1)2-4(x-1)2=9
e) (x+3)2-(x-4)(x+8)=1
f) (2x-1)2+(x+3)2-5(x+7)(x-7)=0
g) 3(x+2)2+(2x-1)2-7(x+3)(x-3)=36
1, ( x+1/3)^3
2, ( 2x+y^2)^3
3, ( 1/2x^2+1/3y)^3
4, ( 3x^2-2y)^3
5, ( 2/3x^2-1/2y)^3
6, ( 2x+1/2)^3
7, ( x-3)^3
8, ( x+1).(X^2+3x+9)
9, ( x-3).( x^2+3x+9)
10, ( x-2).( x^2+2x+4)
11, ( x+4).( x^2-4x+16)
12, ( x-3y).( x^2+3xy+9y^2)
13, ( x^2-1/3). ( x^4+1/3x^2+1/9)
14, ( 1/3x+2y).( 1/9x^2-2/3xy+4y^2)
Đưa về HĐT
2 tháng 10 2020 lúc 18:48
a)(2x-1)^2+(x+3)^2-5(x+7)(x-7)=0
b)(x+2)(x^2-2x+4)-x(x^2+2)=15
c)(x+3)^3-x(3x+1)^2+(2x-1)(4x^2-2x+1)=28
d)(x^2-1)^3-(x^4+x^2+1)(x^2-1)=0
1, tìm x :
a) (x+2).(x+3)-(x-2).(x+5)=0
b) (2x+3).(x-4)+(x-5).(x-2)=(x-4).(3x-5)
c) (3x-5).(7-5x)-(5x+2).(2-3x)=3
d)(x-7).(x+7)-(x-4)2-x=10+3
e) (x+1/2)2-(x-1).(x+1)=2x-1
2, Thu gọn :
a) (x+5)2-(3-x)2-2(x-4).(x+4)
b)4(x-1)2+(2x+3)2-8(x-2)(x+2)
Rút gọn :
1. (2x-5)(3x+1)-(x-3)^2+(2x+5)^2-(3x+1)^3
2. (2x-1)(2x+1)-3x-2)(2x+3)-(x-1)^3+(2x+3)^3
3. (x-2)(x^2+2x+4)-(3x-2)^3+(3x-4)^2
4. (7x-1)(8x+2)-(2x-7)^2-(x-4)^3-(3x+1)^3
5. (5x-1)(5x+1)-(x+3)(x^2-3x+9)-(2x+4)^2-(3x-4)^2+(2x-5)^3
6. (4x-1)(x+2)-(2x+5)^2-(3x-7)^2+(2x+3)^3=(3x-1)^3
Tìm x. biết:
a/12(x-2)(x+2)-3(2x+3)2 =52
b/(2x+1)2 -4(x-1)(x+1)+2x=5
c/(x-2)3-(x-3)(x2+3x+9)+6(x+1)2=15
d/(x+2)(x2-2x+4)-x(x2+2)=15
e/ 12(x-2)(x+2)-3(2x+3)2=57
f/ (3-x)(3+x)+(3x-1)2+6x=522
g/(2x+1)2-4(x-1)(x+1)+2x=5
Rút gọn biểu thực rồi tính : sử dụng các hằng đẳng thức
b) M = (x + 3) ^ 2 + (x - 3)(x - 3) - 2(x + 2)(x - 4) khi 2 thỏa mãn với 2x + 1 = 0
2) V = (3x + 4) ^ 2 - (x + 4)(x - 4) - 10x. khi 2 thỏa mãn với 10x + 1 = 0 .
3) P = (x + 1) ^ 2 - (2x - 1) ^ 2 + 3(x - 2)(x + 2) với x = 1
4) Q = (x - 3)(x + 3) + (x - 2) ^ 2 - 2x(x - 4) với x = - 1 .