lop8 §2 mon toan cau 10 trang 8 luyen tap ☺☺ 27/08/2021 Bởi Sadie lop8 §2 mon toan cau 10 trang 8 luyen tap ☺☺
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 minh xin ctlhn nhe ☺☺ ko sao chep tren mang Bình luận
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 a)(x²-2x+3)(1/2×x-5) =(x²-2x+3)(1/2×x)-5(x²-2x+3) =x²(1/2×x)-2x(1/2×x)+3(1/2×x)-5x²+5×2x-5×3 =(1/2×x³)-x²+3/2×x-5x²+10x-15 =(1/2×x³)-6x²+23/2×x-15 Bình luận
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 minh xin ctlhn nhe ☺☺
ko sao chep tren mang
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
a)(x²-2x+3)(1/2×x-5)
=(x²-2x+3)(1/2×x)-5(x²-2x+3)
=x²(1/2×x)-2x(1/2×x)+3(1/2×x)-5x²+5×2x-5×3
=(1/2×x³)-x²+3/2×x-5x²+10x-15
=(1/2×x³)-6x²+23/2×x-15