a) 2(2x+1)(3x-1)+(2x+1)2+(3x-1)2 = (2x+1+3x-1)2=(5x)2
b) (x-3)(x+3) - (x-3)2= x2-9-x2+6x-9=6x
c) (x2 -1)(x+2) - (x-2)(x2+2x+4)= x3+2x2-x-2-x3+8=2x2-x+6
Đúng hông tar, hình như lag lag chỗ nào đó thì phải á '-'?
Bài làm :
a)=[(2x+1) + (3x-1)]2 = (2x+1+3x-1)2 = (5x)2 = 25x2
b)=(x-3) . [(x+3) - (x-3)] = (x-3)(x+3-x+3) =(x-3) . 6 = 6x - 18
c)= (x2 -1)(x+2) - (x-2)(x+2)2 =(x+2)[(x2 - 1) - (x2 -4 )] = (x+2). 3 = 3x + 6
Chúc bạn học tốt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
a) 2( 2x + 1 )( 3x - 1 ) + ( 2x + 1 )2 + ( 3x - 1 )2
= ( 2x + 1 + 3x - 1 )2
= ( 5x )2 = 25x2
b) ( x - 3 )( x + 3 ) - ( x - 3 )2
= x2 - 9 - ( x2 - 6x + 9 )
= x2 - 9 - x2 + 6x - 9
= 6x - 18
c) ( x2 - 1 )( x + 2 ) - ( x - 2 )( x2 + 2x + 4 )
= x3 + 2x2 - x - 2 - ( x3 - 8 )
= x3 + 2x2 - x - 2 - x3 + 8
= 2x2 - x + 6
a, \(2\left(2x+1\right)\left(3x-1\right)+\left(2x+1\right)^2+\left(3x-1\right)^2\)
\(=12x^2-4x+6x-2+4x^2+4x+1+9x^2-6x+1=25x^2\)
b, \(\left(x-3\right)\left(x+3\right)-\left(x-3\right)^2\)
\(=x^2-9-x^2+6x-9=6x-18\)
c, \(\left(x^2-1\right)\left(x+2\right)-\left(x-2\right)\left(x^2+2x+4\right)\)
\(x^3+2x^2-x-2-x^3+8=2x^2-x+6\)