a)(2x-3)(x+2)
=2x2+4x-3x-6
=2x2+x-6
b)(x-3)(2x+1)-(x-1)2
=(2x2+x-6x-3) - (x2-2x+1)
=(2x2-5x-3) - (x2-2x+1)
=2x2-5x-3-x2+2x-1
=x2-3x-4
Chúc bạn học tốt!
\(a)(2x-3)(x+2)\\=2x^2+4x-3x-6\\=2x^2+x-6\\ b)(x-3)(2x+1)-(x-1)^2\\=2x^2+x-6x-3-x^2+2x-1\\=x^2-3x-4\)
Thực hiện phép tính :
a) \(\left(\dfrac{1}{2}x-1\right)\left(2x-3\right)\)
b) \(\left(x-7\right)\left(x-5\right)\)
c) \(\left(x-\dfrac{1}{2}\right)\left(x+\dfrac{1}{2}\right)\left(4x-1\right)\)
Thực hiện phép tính :
a) \(\left(5x-2y\right)\left(x^2-xy+1\right)\)
b) \(\left(x-1\right)\left(x+1\right)\left(x+2\right)\)
c) \(\dfrac{1}{2}x^2y^2\left(2x+y\right)\left(2x-y\right)\)
Thực hiện phép tính :
a) \(\left(x^2-2x+3\right)\left(\dfrac{1}{2}x-5\right)\)
b) \(\left(x^2-2xy+y^2\right)\left(x-y\right)\)
Làm tính nhân :
a) \(\left(x^2-2x+1\right)\left(x-1\right)\)
b) \(\left(x^3-2x^2+x-1\right)\left(5-x\right)\)
Từ câu b), hãy suy ra kết quả phép nhân : \(\left(x^3-2x^2+x-1\right)\left(x-5\right)\)
Tìm x, biết
a) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
b) \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)
Câu 1: Tìm x:
a. \(\left(x-1\right)\left(x+2\right)-x^2+3=5\)
b. \(\left(2x+1\right)\left(x-3\right)-2x\left(x+7\right)=100\)
c. \(\left(3x-1\right)\left(x+2\right)-\left(2-3x\right)\left(x+3\right)=12\)
Câu 2: Chứng minh giá trị biểu thức sau không phụ thuộc vào biến
\(\left(x-5\right)\left(2x+3\right)-2x\left(x-3\right)+x+7\)
Tìm \(x\) , biết:
a) \(\left(x+2\right)\left(x+3\right)-\left(x-2\right)\left(x+5\right)=6\)
b) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
c) \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)
CÁC BẠN LÀM NHANH GIÚP MIK NHA!
Tìm x biết : (đề không sai)
1.\(-4x\left(x-7\right)+4x\left(x^2-5\right)\) \(=28x^2-13\)
2.\(\left(4x^2-5x\right)\left(3x+2\right)-7x\left(x-7\right)\)= \(\left(-4+x\right)\left(-2x+3\right)+12x^3+2x^2\)
3.\(\left(-4x^2-3\right)\left(2x+5\right)-\left(8x-3\right)\) \(\left(-x^2+2\right)=-5x^2\left(x-6\right)-3x^2-4\)
4.\(\left(x-7\right)\left(x+5\right)-\left(x-3\right)\left(x-2\right)\) \(=15x^2\left(x+1\right)-\left(3x^2-1\right)\) \(\left(5x^2-2\right)-21x^2\)
5.\(\left(x-3\right)\left(-x+10\right)+\left(x-8\right)\left(x+3\right)\) \(=\left(5x^2-1\right)\left(x+3\right)-5x^3-15x^2\)
6.\(\left(-2x^2+5\right)\left(-x+3\right)-x^2\left(2x-6\right)\) \(=\left(x-1\right)\left(x+1\right)-\left(x-2\right)\left(x+4\right)\)
a\(8\left(x+\dfrac{1}{x}\right)^{2^{ }}+4\left(x^{2^{ }}+\dfrac{1}{x^2}\right)-4\left(x^2+\dfrac{1}{x^2}\right)\left(x+\dfrac{1}{x}\right)=\left(x+4\right)^2\)giải các phương trình\(\dfrac{x+4}{2x^2-5x+2}+\dfrac{x+1}{2x^2-7x+3}=\dfrac{2x+5}{2x^2-7x+3}\)
