Bài tập 32 trang 19 sách bài tập (SBT) toán lớp 8 tập 1 cánh diều:Thực hiện phép tính:a)...

{
"answer1": "a) $7x^{2}y^{5}-\frac{7}{3}y^{2}(3x^{2}y^{3}+1) = 7x^{2}y^{5}-7x^{2}y^{5}-\frac{7}{3}y^{2} = -\frac{7}{3}y^{2}$; b) $\frac{1}{2}x(x^{2}+y^{2})-\frac{3}{2}y^{2}(x+1)-\frac{1}{\sqrt{4}}x^{3} = \frac{1}{2}x^{3}+\frac{1}{2}xy^{2}-\frac{3}{2}yx^{2}-x^{3} = -\frac{1}{2}x^{3}+\frac{1}{2}xy^{2}-\frac{3}{2}yx^{2}$; c) (x + y)(x2 + y2 + 3xy) ‒ x3 ‒ y3 = x^{3}+xy^{2}+3x^{2}y+x^{2}+y^{3}+3xy^{2}-x^{3}-y^{3} = 3xy^{2}+3x^{2}y+x^{2}+y^{2}$",
"answer2": "a) $7x^{2}y^{5}-\frac{7}{3}y^{2}(3x^{2}y^{3}+1) = 7x^{2}y^{5}-\frac{7}{3}y^{2}*3x^{2}y^{3}-\frac{7}{3}y^{2}=7x^{2}y^{5}-7x^{2}y^{5}-7y^{2}= -7y^{2}$; b) $\frac{1}{2}x(x^{2}+y^{2})-\frac{3}{2}y^{2}(x+1)-\frac{1}{\sqrt{4}}x^{3} = \frac{1}{2}x^{3}+\frac{1}{2}xy^{2}-\frac{3}{2}yx^{2}-x^{3} = -\frac{1}{2}x^{3}+\frac{1}{2}xy^{2}-\frac{3}{2}yx^{2}$; c) (x + y)(x2 + y2 + 3xy) ‒ x3 ‒ y3 = x^{3}+y^{3}+3xy+x^{2}+y^{2}+3xy^{2}-x^{3}-y^{3}=3xy^{2}+3x^{2}y+x^{2}+y^{2}$",
"answer3": "a) $7x^{2}y^{5}-\frac{7}{3}y^{2}(3x^{2}y^{3}+1) = 7x^{2}y^{5}-\frac{7}{3}y^{2}*3x^{2}y^{3}-\frac{7}{3}y^{2}=7x^{2}y^{5}-21x^{2}y^{5}-\frac{7}{3}y^{2}= -21x^{2}y^{5}-\frac{7}{3}y^{2}$; b) $\frac{1}{2}x(x^{2}+y^{2})-\frac{3}{2}y^{2}(x+1)-\frac{1}{\sqrt{4}}x^{3} = \frac{1}{2}x^{3}+\frac{1}{2}xy^{2}-\frac{3}{2}yx^{2}-x^{3} = -\frac{1}{2}x^{3}+\frac{1}{2}xy^{2}-\frac{3}{2}yx^{2}$; c) (x + y)(x2 + y2 + 3xy) ‒ x3 ‒ y3 = x^{3}+y^{3}+3xy+x^{2}+y^{2}+3xy^{2}-x^{3}-y^{3}=3xy^{2}+3x^{2}y+x^{2}+y^{2}$"
}