( x - 5 ) ( x - 7 ) = x\(^2\) - 5x - 7x + 35 = x\(^2\) - 12x + 35
( x - 5 ) ( x - 7 ) = x\(^2\) - 5x - 7x + 35 = x\(^2\) - 12x + 35
Tính(rút gọn)
1, x^ 2 - 2x + 5 - (x - 7)(x + 2)
2,-5x(x-5)+(x-3)(x^2-7)
3, x(x^2-x-2)-(x+5)(x-1)
4, (-x+5)(x+3)+(2x-1)(x+3)
5, -4x(x+3)(x-4)-3x(x^2-x+1)
5) D=(x-7)*(x+5)-(x-4)*(x+3)
6) E= 4x*(x2-x-1)-(x+3)*(x2-2)
7) F= 5x*(x-3)*(x-1)-4x*(x2-2x)
Rút gọn biểu thức
a, (x-2).(x+2)+(x-3).(x+3)-2x^2
b, (x+5).(x-5)+(x-7).(x+7)-2x^2
Bài 3: Áp dụng đẳng thức trên thực hiện phép nhân bằng cách cho a, b là một số cho trước. ( mỗi ý 10 câu, rồi tính...) Hãy tính:
1) ( x+3)( x+ 5) =
2) (x+6)(x+2)
3) (x+3)(x+7)
4) ( x- 3)( x-5)
5) (x-4)(x-9)
6) (x-10)(x-12)
7) (x+3)(x-5)
8) (x_8)(x+3)
9) (x+8)(x-4) 10) ( 2x-1)( 3x-2)
11)(3x+1)( 5x-3)
1) (\(\dfrac{1}{2}\)x + 3)*(x2- 4x- 6)
2) (6x2 -9x +15)*(\(\dfrac{2}{3}\)x+1)
3) (3x2 -x+5)*(x3+5x-1)
4) (x-1)*(x+1)*(x-2)
5) D=(x-7)*(x+5)-(x-4)*(x+3)
6) E= 4x*(x2-x-1)-(x+3)*(x2-2)
7) F= 5x*(x-3)*(x-1)-4x*(x2-2x)
giải phương trình :
\(\dfrac{x-5}{x-5}+\dfrac{x-6}{x-5}+\dfrac{x-7}{x-5}...\dfrac{1}{x-5}=4\)
(xϵN)
(3x-1)(2x+7)-(x+1)(6x-5)=x-2-(x-5)
Bài 1
1) (x^2-2x+3)*(x-4)
2) (2x^2-3x-1)*(5x+2)
3) (x^2-2xy+y^2)*(y^2+2xy+x^2+1)
4) (x-7)*(x+5)*(x-5)
5) (x+2y)*(x-y)
6) (x+5)*(x^2-2x+3)
7) 2x(x+5)*(x-1)
8) (x-2y)*(x+2y)
9) (x-1)*(x^2+x+1)
10) (1-2x^2+x)*(x-4+x^2)
(4*x+2)*(7 -3*x)+(x-5)*(12*x+4)