NN
2
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Các câu hỏi dưới đây có thể giống với câu hỏi trên
31 tháng 8 2021
x2 + 6x - y2 + 9 =
= ( x2 + 6x + 9 ) - y2
= ( x + 3 )2 - y2
= ( x + 3 - y ) . ( x + 3 + y )
Hok tốt!!!!!!!!!!!
5 tháng 8 2018
a) \(x^2-6x+8=x^2-4x-2x+8=x\left(x-4\right)-2\left(x-4\right)=\left(x-4\right)\left(x-2\right)\)
b) \(x^2-4x+3=x^2-x-3x+3=x\left(x-1\right)-3\left(x-1\right)=\left(x-1\right)\left(x-3\right)\)
c) \(x^2-x-12=x^2-4x+3x-12=x\left(x-4\right)+3\left(x-4\right)=\left(x-4\right)\left(x+3\right)\)
5 tháng 8 2018
a) x^2 -6x +8
= x^2 - 2x -4x +8
= x(x -2) - 4 ( x-2)
= (x-2)(x-4)
b) x^2 - 4x +3
= x^2 -x - 3x +3
= x(x-1) -3(x-1)
= (x-1)(x-3)
5 tháng 8 2018
\(x^2-6x+8\)
\(=x^2-2x-4x+8\)
\(=x\left(x-2\right)-4\left(x-2\right)\)
\(=\left(x-4\right)\left(x-2\right)\)
\(x^2-4x+3\)
\(=x^2-x-3x+3\)
\(=x\left(x-1\right)-3\left(x-1\right)\)
\(=\left(x-3\right)\left(x-1\right)\)
\(x^2-x-12\)
\(=x^2-4x+3x-12\)
\(=x\left(x-4\right)+3\left(x-4\right)\)
\(=\left(x+3\right)\left(x-4\right)\)
5 tháng 8 2018
a) \(x^2-6x+8=x^2-2x-4x+8=x\left(x-2\right)-4\left(x-2\right)\\ =\left(x-2\right)\left(x-4\right)\)
b) \(x^2-4x+3=x^2-x-3x+3=x\left(x-1\right)-3\left(x-1\right)\\ =\left(x-1\right)\left(x-3\right)\)
c) \(x^2-x-12=x^2+3x-4x-12=x\left(x+3\right)-4\left(x+3\right)\\ =\left(x+3\right)\left(x-4\right)\)
2 tháng 7 2018
a) \(x^2+3x+2\)
\(=\left(x^2+2x\right)+\left(x+2\right)\)
\(=x\left(x+2\right)+\left(x+2\right)\)
\(=\left(x+1\right)\left(x+2\right)\)
b) \(x^2+5x+6\)
\(=\left(x^2+2x\right)+\left(3x+6\right)\)
\(=x\left(x+2\right)+3\left(x+2\right)\)
\(=\left(x+3\right)\left(x+2\right)\)
c) \(x^2+5x+6\)
( giống câu b -_- )
d) \(x^2+7x+12\)
\(=\left(x^2+4x\right)+\left(3x+12\right)\)
\(=x\left(x+4\right)+3\left(x+4\right)\)
\(=\left(x+3\right)\left(x+4\right)\)
MA
2 tháng 7 2018
\(1,x^2+3x+2\)
\(=x^2+x+2x+2\)
\(=x\left(x+1\right)+2\left(x+1\right)\)
\(=\left(x+2\right)\left(x+1\right)\)
\(2,x^2+5x+6\)
\(=x^2+2x+3x+6\)
\(=x\left(x+2\right)+3\left(x+2\right)\)
\(=\left(x+3\right)\left(x+2\right)\)
\(4,x^2+7x+12\)
\(=x^2+3x+4x+12\)
\(=x\left(x+3\right)+4\left(x+3\right)\)
\(=\left(x+4\right)\left(x+3\right)\)
\(5,x^2-4x+3\)
\(=x^2-x-3x+3\)
\(=x\left(x-1\right)-3\left(x-1\right)\)
\(=\left(x-3\right)\left(x-1\right)\)
\(6,x^2+3x-4\)
\(=x^2-x+4x-4\)
\(=x\left(x-1\right)+4\left(x-1\right)\)
\(=\left(x+4\right)\left(x-1\right)\)
\(8,x^2-3x-10\)
\(=x^2-5x+2x-10\)
\(=x\left(x-5\right)+2\left(x-5\right)\)
\(=\left(x+2\right)\left(x-5\right)\)
VH
1
\(x^2+6x-7\)
\(\Rightarrow x^2-x+7x-7\)
\(\Rightarrow x\left(x-1\right)+7\left(x-1\right)\)
\(\Rightarrow\left(x-1\right)\left(x+7\right)\)
\(x^2+6x-7\)
\(=x^2+2.x.3+3^2-3^2-7\)
=\(\left(x+3\right)^2-9-7\)
=\(\left(x+3\right)^2-16\)
\(=\left(x+3\right)^2-\sqrt{16}^2\)
\(=\left(x+3-\sqrt{16}\right).\left(x+3-\sqrt{16}\right)\)