(2x +3y )$^{2}$ ( 5x -y)$^{2}$ ( x+$\frac{1}{4}$) $^{2}$ 05/08/2021 Bởi Margaret (2x +3y )$^{2}$ ( 5x -y)$^{2}$ ( x+$\frac{1}{4}$) $^{2}$
Đáp án: Giải thích các bước giải: a, (2x + 3y)²= 4x²+12xy+9y² b, (5x-y)²= 25x² – 10xy + y² c, (x+1/4 )²= x² + 1/2x+1/16 Bình luận
$\begin{array}{l} + )\,\,{\left( {2x + 3y} \right)^2} = {\left( {2x} \right)^2} + 2.2x.3y + {\left( {3y} \right)^2} = 4{x^2} + 12xy + 9{y^2}\\ + )\,\,{\left( {5x – y} \right)^2} = {\left( {5x} \right)^2} – 2.5x.y + {y^2} = 25{x^2} – 10xy + {y^2}\\ + )\,\,{\left( {x + \dfrac{1}{4}} \right)^2} = {x^2} + 2.x.\dfrac{1}{4} + {\left( {\dfrac{1}{4}} \right)^2} = {x^2} + \dfrac{1}{2}x + \dfrac{1}{{16}}\end{array}$ Bình luận
Đáp án:
Giải thích các bước giải:
a, (2x + 3y)²= 4x²+12xy+9y²
b, (5x-y)²= 25x² – 10xy + y²
c, (x+1/4 )²= x² + 1/2x+1/16
$\begin{array}{l}
+ )\,\,{\left( {2x + 3y} \right)^2} = {\left( {2x} \right)^2} + 2.2x.3y + {\left( {3y} \right)^2} = 4{x^2} + 12xy + 9{y^2}\\
+ )\,\,{\left( {5x – y} \right)^2} = {\left( {5x} \right)^2} – 2.5x.y + {y^2} = 25{x^2} – 10xy + {y^2}\\
+ )\,\,{\left( {x + \dfrac{1}{4}} \right)^2} = {x^2} + 2.x.\dfrac{1}{4} + {\left( {\dfrac{1}{4}} \right)^2} = {x^2} + \dfrac{1}{2}x + \dfrac{1}{{16}}
\end{array}$