a,(2x^2-3x).(5x^2-2x+1) b,(x-2y).(3xy+5y^2+x) 31/08/2021 Bởi Madeline a,(2x^2-3x).(5x^2-2x+1) b,(x-2y).(3xy+5y^2+x)
Đáp án: b.(x – 2y)(3xy + 5y^2 + x) = x.(3xy + 5y^2 + x) + (-2y).(3xy + 5y^2 + x) = x.3xy + x.5y^2 + x.x + (-2y).3xy + (–2y).5y^2 + (–2y).x = 3x^2y + 5xy^2 + x^2 – 6xy2 – 10y^3 – 2xy = 3x^2y + (5xy^2 – 6xy^2) + x^2 – 10y^3 – 2xy = 3x^2y – xy^2 + x^2 – 10y^3 – 2xy a.(2x^2 – 3x)(5x^2 – 2x + 1) = 2x^2(5x^2 – 2x + 1) + (-3x)(5x^2 – 2x + 1) = 2x^2.5x^2 + 2x^2.(-2x) + 2x^2.1 + (–3x).5x^2 + (-3x).(-2x) + (-3x).1 = (2.5)(x^2.x^2) + [2. (-2)].(x^2.x) + 2x^2 + [(-3).5].(x.x^2) + [(-3).(-2).(x.x) + (-3x)] = 10x^4 – 4x^3 + 2x^2 – 15x^3 + 6x^2 – 3x = 10x^4 – (4x^3 + 15x^3) + (2x^2 + 6x^2) – 3x = 10x^4 – 19x^3 + 8x^2 – 3x Bình luận
a) `(2x²-3x).(5x²-2x+1)` `= 2x².5x²-2x².2x+2x².1-3x.5x²-3x.2x+3x.1` `= 10x^4-4x³+2x²-15x³-6x²+3x` `= 10x^4-(4x³-15x³)+(2x²-6x²)+3x` `= 10x^4-19x³-4x²+3x` b) `(x-2y).(3xy+5y²+x)` `= x.3xy+x.5y²+x.x-2y.3xy+2y.5y²+2y.x` `= 3x²y+5xy²+x²-6x²y+10y³+2xy` `= (3x²y-6x²y)+5xy²+10y³+2xy+x²` `= -3x²y+5xy²+10y³+2xy+x²` Bình luận
Đáp án:
b.(x – 2y)(3xy + 5y^2 + x)
= x.(3xy + 5y^2 + x) + (-2y).(3xy + 5y^2 + x)
= x.3xy + x.5y^2 + x.x + (-2y).3xy + (–2y).5y^2 + (–2y).x
= 3x^2y + 5xy^2 + x^2 – 6xy2 – 10y^3 – 2xy
= 3x^2y + (5xy^2 – 6xy^2) + x^2 – 10y^3 – 2xy
= 3x^2y – xy^2 + x^2 – 10y^3 – 2xy
a.(2x^2 – 3x)(5x^2 – 2x + 1)
= 2x^2(5x^2 – 2x + 1) + (-3x)(5x^2 – 2x + 1)
= 2x^2.5x^2 + 2x^2.(-2x) + 2x^2.1 + (–3x).5x^2 + (-3x).(-2x) + (-3x).1
= (2.5)(x^2.x^2) + [2. (-2)].(x^2.x) + 2x^2 + [(-3).5].(x.x^2) + [(-3).(-2).(x.x) + (-3x)]
= 10x^4 – 4x^3 + 2x^2 – 15x^3 + 6x^2 – 3x
= 10x^4 – (4x^3 + 15x^3) + (2x^2 + 6x^2) – 3x
= 10x^4 – 19x^3 + 8x^2 – 3x
a) `(2x²-3x).(5x²-2x+1)`
`= 2x².5x²-2x².2x+2x².1-3x.5x²-3x.2x+3x.1`
`= 10x^4-4x³+2x²-15x³-6x²+3x`
`= 10x^4-(4x³-15x³)+(2x²-6x²)+3x`
`= 10x^4-19x³-4x²+3x`
b) `(x-2y).(3xy+5y²+x)`
`= x.3xy+x.5y²+x.x-2y.3xy+2y.5y²+2y.x`
`= 3x²y+5xy²+x²-6x²y+10y³+2xy`
`= (3x²y-6x²y)+5xy²+10y³+2xy+x²`
`= -3x²y+5xy²+10y³+2xy+x²`