\(4x^2-25+\left(2x+7\right).\left(5-2x\right)\)

\(=\left(2x+5\right).\left(2x-5\right)-\left(2x+7\right).\left(2x-5\right)\)

\(=\left(2x+5-2x-7\right).\left(2x-5\right)\)

\(=-2.\left(2x-5\right)\)

\(a^2x^2-a^2x^2-b^2x^2+b^2y^2\)

\(=a^2.\left(x^2-y^2\right)-b^2.\left(x^2-y^2\right)\)

\(=\left(a^2-b^2\right).\left(x^2-y^2\right)\)

\(=\left(a-b\right).\left(a+b\right).\left(x-y\right).\left(x+y\right)\)

\(x^2-y^2+12y-36\)

\(=x^2-\left(y^2-12y+36\right)\)

\(=x^2-\left(y-6\right)^2\)

\(=\left(x-y+6\right).\left(x+y-6\right)\)

\(\left(x+2\right)^2-x^2+2x-1\)

\(=\left(x+2\right)^2-\left(x^2-2x+1\right)\)

\(=\left(x+2\right)^2-\left(x-1\right)^2\)

\(=[x+2-\left(x-1\right)].[x+2+\left(x-1\right)]\)

\(=\left(x+2-x+1\right).\left(x+2+x-1\right)\)

\(=3.\left(2x+1\right)\)

\(16x^2-y^2=\left(4x\right)^2-y^2=\left(4x-y\right).\left(4x+y\right)\)

\(1+27x^3=1^3+\left(3x\right)^3=\left(1+3x\right).\left(1-3x+9x^2\right)\)

\(4x^2-4x-3\)

\(=4x^2-2x+6x-3\)

\(=2x.\left(x-1\right)+3.\left(x-1\right)\)

\(=\left(2x+3\right).\left(x-1\right)\)

\(x^2-4x+3\)

\(=x^2-3x-x+3\)

\(=\left(x^2-x\right)-\left(3x-3\right)\)

\(=x.\left(x-1\right)-3.\left(x-1\right)\)

\(=\left(x-3\right).\left(x-1\right)\)

\(x^4-8x+63\)

\(=x^4+4x^3+9x^2-4x^3-16x^2-36x+7x^2+28x+63\)

\(=\left(x^4+4x^3+9x^2\right)-\left(4x^3+16x^2+36x\right)+\left(7x^2+28x+63\right)\)

\(=x^2.\left(x^2+4x+9\right)-4x.\left(x^2+4x+9\right)+7.\left(x^2+4x+9\right)\)

\(=\left(x^2-4x+7\right).\left(x^2+4x+9\right)\)

\(\left(4x^4+4x^3-16x^2-16x\right):\left(4x+4\right)\)

\(=[\left(4x^4+4x^3\right)-\left(16x^2+16x\right)]:\left(4x+4\right)\)

\(=[4x^3.\left(x+1\right)-16x.\left(x+1\right)]:\left(4x+4\right)\)

\(=[\left(4x^3-16x\right).\left(x+1\right)]:\left(4x+4\right)\)

\(=[4.\left(x^3-4x\right).\left(x+1\right)]:[4.\left(x+1\right)]\)

\(=\frac{4.\left(x+1\right).\left(x^3-4x\right)}{4.\left(x+1\right)}\)

\(=x^3-4x\)

\(\left(x^4-2x^3+2x-1\right):\left(x^2-1\right)\)

\(=\left(x^4-2x^3+x^2-x^2+2x-1\right):\left(x^2-1\right)\)

\(=[x^2.\left(x^2-2x+1\right)-\left(x^2-2x+1\right)]:\left(x^2-1\right)\)

\(=\left(x^2-1\right).\left(x^2-2x+1\right):\left(x^2-1\right)\)

\(=x^2-2x+1\)

\(=\left(x-1\right)^2\)

chỗ AB < AC kia các bn chuyển thành chữ " và " nhé. Mk viết nhầm

Câu 1:

a) (-4xy)(2xy-3xy²+5)

= -8x²y²+12x²y³-20xy

b) (2x-3)(6xy-5x²y+2)

= 12x²y-10x³y+4x-18xy+15x²y-6

=28x²y-10x³y-18xy+4x-6

Câu 2:

a) x²+2x+1 = (x+1)²

b) 4x²-9y² = (2x+3y)(2x-3y)

c) 2x+4y-x-2y = x+2y

Câu 3:
tại x,y bằng bao nhiêu chưa cho biết nên câu 3 bỏ qua

HOK TỐT~

2x-x=x

4y-2y=2y

\(\Rightarrow\)Kết quả là x+2y

x + 1 = 2

x       = 2 - 1

x       = 1

@Bảo

#Cafe