Câu 1 :
a ) 3x ( 2x – 3 )
b ) ( 2x – 1 ) ( 2x + 1 )
c ) 3x ( x – 5 ) – 3x ²
Câu 1 : a ) 3x ( 2x – 3 ) b ) ( 2x – 1 ) ( 2x + 1 ) c ) 3x ( x – 5 ) – 3x ²
By Abigail
By Abigail
Câu 1 :
a ) 3x ( 2x – 3 )
b ) ( 2x – 1 ) ( 2x + 1 )
c ) 3x ( x – 5 ) – 3x ²
a ) 3x ( 2x – 3 )
= 6x² – 9x
b ) ( 2x – 1 ) ( 2x + 1 )
= ( 2x )² – 1²
c ) 3x ( x – 5 ) – 3x ²
= 3x² – 15x – 3x²
= – 15x
Đáp án + giải thích các bước giải:
`a ) 3x ( 2x – 3 )`
`=6x^2-9x`
` b ) ( 2x – 1 ) ( 2x + 1 )`
`=4x^2+2x-2x-1`
`=4x^2-1`
` c ) 3x ( x – 5 ) – 3x^2`
`=3x^2-15x -3x^2`
`=-15x`