Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1.Tuan find playing table tennis interesting because he plays with his best friend.
2. My brother doesn't ice-skating because he thinks it is dangerous.
3. Why don;t you take jogging? It helps you keep fit.
4.My son and I love water so we go surfing together very summer.
5.You need to be patient to make beautiful gifts from eggshells.
6.I think you should take up jogging bacause it is suitable for health condition.
Answer:
a) Điều kiện: \(x\ne1;x\ne-1\)
\(\left(\frac{x+x^3}{1-x^2}-\frac{x-x^3}{1+x^2}\right):\left(\frac{1+x}{1-x}-\frac{1-x}{1+x}\right)\)
\(=\frac{x.\left(1+x^2\right)^2-x.\left(1-x^2\right)^2}{\left(1+x^2\right).\left(1-x^2\right)}:\frac{\left(1+x\right)^2-\left(1-x\right)^2}{1-x^2}\)
\(=\frac{x.\left(1+2x^2+x^4\right)-x.\left(1-2x^2+x^4\right)}{\left(1+x^2\right).\left(1-x^2\right)}.\frac{1-x^2}{1+2x+x^2-1+2x-x^2}\)
\(=\frac{x^5+2x^3+x-x+2x^3-x^5}{\left(1+x^2\right).\left(1-x^2\right)}.\frac{1-x^2}{4x}\)
\(=\frac{4x^3}{\left(1+x^2\right).\left(1-x^2\right)}.\frac{1-x^2}{4x}\)
\(=\frac{x^2}{1+x^2}\)
b) Điều kiện: \(x\ne0;x\ne1\)
\(\frac{x+x}{x^2+x+1}-\left(\frac{2x^3+x^2-x}{x^3-1}-2-\frac{1}{x-1}\right):\frac{2x-1}{x-x^2}\)
\(=\frac{x^2+x}{x^2+x+1}-\frac{2x^3+x^2-x-2\left(x^3-1\right)-x^2-x-1}{\left(x-1\right).\left(x^2+x+1\right)}.\frac{x.\left(1-x\right)}{2x-1}\)
\(=\frac{x^2+x}{x^2+x+1}-\frac{2x^3-2x-1-2x^3+2}{\left(x-1\right).\left(x^2+x+1\right)}.\frac{-x\left(x-1\right)}{2x-1}\)
\(=\frac{x^2+x}{x^2+x+1}+\frac{-2x+1}{\left(x-1\right).\left(x^2+x+1\right)}.\frac{x.\left(x-1\right)}{2x-1}\)
\(=\frac{x^2+x}{x^2+x+1}-\frac{x}{x^2+x+1}\)
\(=\frac{x^2}{x^2+x+1}\)
chu vi hình vuông là:
24.4= 96
diện tích hình vuông là:
24. 24= 576
đáp số: a, 96
b, 576
chúc bạn học tốt!!!
a, \(\left(x-2\right)^2+\left(3-x\right)\cdot\left(x-1\right)\)
\(=x^2-4x+4+\left(3x-3-x^2+x\right)\)
\(=x^2-4x+4+3x-3-x^2+x\)
\(=1\)
b, \(\left(x+2\right)^3-x\cdot\left(x^2+6x+12\right)\)
\(=x^3+6x^2+12x+8-x^3-6x^2-12x\)
\(=8\)
bằng 747
747 nha em chúc e học giỏi