làm giúp mình với mình cảm ơn lớp 8 môn toán hk 1 bài 2 trang 8 câu 10 ☺☺ 21/08/2021 Bởi Valentina làm giúp mình với mình cảm ơn lớp 8 môn toán hk 1 bài 2 trang 8 câu 10 ☺☺
`a, (x² – 2x + 3) (1/2x – 5)` `=1/2x³ – 5x² – x² +10x + 3/2x – 15` `= 1/2x³ – 6x² + 23/2x -15` `b) (x² – 2xy + y²)(x – y)` `= (x² – 2xy + y²).x + (x² – 2xy + y²).(–y)` `= x².x + (–2xy).x + y².x + x².(–y) + (–2xy).(–y) + y².(–y)` `= x³ – 2x²y + xy² – x²y + 2xy² – y³` `= x³ – (2x²y + x²y) + (xy² + 2xy²) – y²` `= x³ – 3x²y + 3xy² – y³` Xin hay nhất ! Bình luận
Đáp án: a) (x2 – 2x + 3) (1/2x – 5) =1/2x3 – 5x2 – x2 +10x + 3/2x – 15 = 1/2x3 – 6x2 + 23/2 x -15 b) (x2 – 2xy + y2)(x – y) = (x2 – 2xy + y2).x + (x2 – 2xy + y2).(–y) = x2.x + (–2xy).x + y2.x + x2.(–y) + (–2xy).(–y) + y2.(–y) = x3 – 2x2y + xy2 – x2y + 2xy2 – y3 = x3 – (2x2y + x2y) + (xy2 + 2xy2) – y3 = x3 – 3x2y + 3xy2 – y3. cho mình xin ctlnh nhé chúc bạn học tốt ☺☺ Bình luận
`a, (x² – 2x + 3) (1/2x – 5)`
`=1/2x³ – 5x² – x² +10x + 3/2x – 15`
`= 1/2x³ – 6x² + 23/2x -15`
`b) (x² – 2xy + y²)(x – y)`
`= (x² – 2xy + y²).x + (x² – 2xy + y²).(–y)`
`= x².x + (–2xy).x + y².x + x².(–y) + (–2xy).(–y) + y².(–y)`
`= x³ – 2x²y + xy² – x²y + 2xy² – y³`
`= x³ – (2x²y + x²y) + (xy² + 2xy²) – y²`
`= x³ – 3x²y + 3xy² – y³`
Xin hay nhất !
Đáp án:
a) (x2 – 2x + 3) (1/2x – 5)
=1/2x3 – 5x2 – x2 +10x + 3/2x – 15
= 1/2x3 – 6x2 + 23/2 x -15
b) (x2 – 2xy + y2)(x – y)
= (x2 – 2xy + y2).x + (x2 – 2xy + y2).(–y)
= x2.x + (–2xy).x + y2.x + x2.(–y) + (–2xy).(–y) + y2.(–y)
= x3 – 2x2y + xy2 – x2y + 2xy2 – y3
= x3 – (2x2y + x2y) + (xy2 + 2xy2) – y3
= x3 – 3x2y + 3xy2 – y3.
cho mình xin ctlnh nhé
chúc bạn học tốt ☺☺