1
a 2x3(x2-4x+5)
= 2x5-8x4+10x3
b (2x-1)(3x3-4)
=2x(3x3-4)-1(3x3-4)
=6x4-8x-3x3+4
1. Tính.
a) 2x3 (x2 - 4x + 5)
= \(2x^3.x^2+2x^3.\left(-4x\right)+2x^3.5\)
= \(2x^5-8x^4+10x^3\)
b) (2x -1)(3x3 - 4)
\(=2x.3x^3+2x.\left(-4\right)+\left(-1\right).3x^3+\left(-1\right).\left(-4\right)\)
\(=6x^4-8x-3x^3+4\)
Câu 1\(a,2x^3.\left(x^2-4x+5\right)\)
\(=2x^5-8x^4+10x^3\)
b,\(\left(2x+1\right)\left(3x^3-4\right)\)
\(=6x^4-8x-3x^3+4\)
Câu 2
a,\(9x^2-y^2=\left(3x^2\right)-y^2\)
=\(\left(3x+y\right)\left(3x-y\right)\)
b,\(x^2-5x+4\)
\(\Leftrightarrow x^2-x-4x+4\)
\(\Leftrightarrow\left(x^2-x\right)-\left(4x+4\right)\)
\(\Leftrightarrow x\left(x-1\right)-4\left(x-1\right)\)
\(\Leftrightarrow\left(x-4\right)\left(x-1\right)\)
bài 1 mik ko hỉu ~.~
2)
a) 9x2- y2= (3x)2-y2= (3x+y).(3x-y)
ý b ) mik ko pít ~ cứ thấy sai sai đầu bài ~
2
b x2-5x+4
=x2-x-4x+4
=x(x-1)-4(x-1)
=(x-4)(x-1)