\(a)-2y(5xy+3x^2)\\=-10xy^2-6x^2y\\b)(2x+y)(4x-y)\\=8x^2-2xy+4xy-y^2\\=8x^2+2xy-y^2\\c)(x-1^2)-(x+1^2)\\=(x-1)-(x+1)\\=x-1-x-1\\=-2(bạn.xem.lại.đề.phần.này)\\d)(xem.lại.đề)\)

\(15.\sqrt{4x-12}+2\sqrt{9x-27}-\sqrt{36}=\sqrt{25x-75}\\ \sqrt{4\left(x-3\right)}+2\sqrt{9\left(x-3\right)}-6=\sqrt{25\left(x-3\right)}\\ 2\sqrt[]{x-3}+6\sqrt{x-3}-6-5\sqrt{x-3}\\ =3\sqrt{x-3}-6\)

\((x+2)(x^2-2x+1)\\=x^3-2x^2+x+2x^2-4x+2\\=x^3-3x+2\\=> ChọnA\)

D AAbb

Bạn vào Tex gõ 3\sqrt{x+1} sẽ ra \(3\sqrt{x+1}\)

D.\(2022.7^3 +49\\\)

\(2022.7^3⋮7\)
\(49⋮7\)

\(\Rightarrow2022.7^3+49⋮7\)