a) (2x+3y)^2= b) (5x-y)^2= c) (x^2+ 2/5y).(x^2-2/5y)= d) (x+1/4)^2= e) (x+2y+z).(x+2y-z)= f) (5+3x)^3= 21/08/2021 Bởi Eliza a) (2x+3y)^2= b) (5x-y)^2= c) (x^2+ 2/5y).(x^2-2/5y)= d) (x+1/4)^2= e) (x+2y+z).(x+2y-z)= f) (5+3x)^3=
Đáp án: \(a)\ (2x+3y)^{2}=4x^{2}+12xy+9y^{2}\\ b)\ (5x-y)^{2}=25x^{2}-10xy+y^{2}\\ c)\ \bigg(x^{2}+\dfrac{2}{5}y\bigg)\bigg(x^{2}-\dfrac{2}{5}y\bigg)=x^{4}-\dfrac{4}{25}y^{2}\\ d)\ \bigg(x+\dfrac{1}{4}\bigg)^{2}=x^{2}+\dfrac{1}{2}x+\dfrac{1}{16}\\ e)\ (x+2y+z)(x+2y-z)=(x+2y)^{2}-z^{2}\\ f)\ (5+3x)^{3}=125+225x+135x^{2}+27x^{3}\) Giải thích các bước giải: \(a)\ (2x+3y)^{2}=(2x)^{2}+2.2x.3y+(3y)^{2}=4x^{2}+12xy+9y^{2}\\ b)\ (5x-y)^{2}=(5x)^{2}-2.5x.y+y^{2}=25x^{2}-10xy+y^{2}\\ c)\ \bigg(x^{2}+\dfrac{2}{5}y\bigg)\bigg(x^{2}-\dfrac{2}{5}y\bigg)=(x^{2})^{2}-\bigg(\dfrac{2}{5}y\bigg)^{2}=x^{4}-\dfrac{4}{25}y^{2}\\ d)\ \bigg(x+\dfrac{1}{4}\bigg)^{2}=x^{2}+2.x.\dfrac{1}{4}+\bigg(\dfrac{1}{4}\bigg)^{2}=x^{2}+\dfrac{1}{2}x+\dfrac{1}{16}\\ e)\ (x+2y+z)(x+2y-z)=(x+2y)^{2}-z^{2}\\ f)\ (5+3x)^{3}=5^{3}+3.5^{2}.3x+3.5.(3x)^{2}+(3x)^{3}=125+225x+135x^{2}+27x^{3}\) chúc bạn học tốt! Bình luận
`a) (2x+3y)^2= 4x^2+ 12xy+ 9y^2` `b) (5x-y)^2= 25x^2- 10xy+ y^2` `c) (x^2+ 2/5 y).(x^2- 2/5y)=x^4- 4/25y^2` `d) (x+ 1/4)^2=x^2+ 1/2 x+ 1/16` `e) (x+2y+z)(x+2y-z)=(x+2y)^2- z^2` `f) (5+3x)^3=125+225y+135y^2+ 27x^3` chúc học tốt Bình luận
Đáp án:
\(a)\ (2x+3y)^{2}=4x^{2}+12xy+9y^{2}\\ b)\ (5x-y)^{2}=25x^{2}-10xy+y^{2}\\ c)\ \bigg(x^{2}+\dfrac{2}{5}y\bigg)\bigg(x^{2}-\dfrac{2}{5}y\bigg)=x^{4}-\dfrac{4}{25}y^{2}\\ d)\ \bigg(x+\dfrac{1}{4}\bigg)^{2}=x^{2}+\dfrac{1}{2}x+\dfrac{1}{16}\\ e)\ (x+2y+z)(x+2y-z)=(x+2y)^{2}-z^{2}\\ f)\ (5+3x)^{3}=125+225x+135x^{2}+27x^{3}\)
Giải thích các bước giải:
\(a)\ (2x+3y)^{2}=(2x)^{2}+2.2x.3y+(3y)^{2}=4x^{2}+12xy+9y^{2}\\ b)\ (5x-y)^{2}=(5x)^{2}-2.5x.y+y^{2}=25x^{2}-10xy+y^{2}\\ c)\ \bigg(x^{2}+\dfrac{2}{5}y\bigg)\bigg(x^{2}-\dfrac{2}{5}y\bigg)=(x^{2})^{2}-\bigg(\dfrac{2}{5}y\bigg)^{2}=x^{4}-\dfrac{4}{25}y^{2}\\ d)\ \bigg(x+\dfrac{1}{4}\bigg)^{2}=x^{2}+2.x.\dfrac{1}{4}+\bigg(\dfrac{1}{4}\bigg)^{2}=x^{2}+\dfrac{1}{2}x+\dfrac{1}{16}\\ e)\ (x+2y+z)(x+2y-z)=(x+2y)^{2}-z^{2}\\ f)\ (5+3x)^{3}=5^{3}+3.5^{2}.3x+3.5.(3x)^{2}+(3x)^{3}=125+225x+135x^{2}+27x^{3}\)
chúc bạn học tốt!
`a) (2x+3y)^2= 4x^2+ 12xy+ 9y^2`
`b) (5x-y)^2= 25x^2- 10xy+ y^2`
`c) (x^2+ 2/5 y).(x^2- 2/5y)=x^4- 4/25y^2`
`d) (x+ 1/4)^2=x^2+ 1/2 x+ 1/16`
`e) (x+2y+z)(x+2y-z)=(x+2y)^2- z^2`
`f) (5+3x)^3=125+225y+135y^2+ 27x^3`
chúc học tốt