1. \(\frac{x + 3}{x^{2} - 1} - \frac{1}{x^{2} - x}\)

\(\frac{x + 3}{\left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)} - \frac{1}{x \left(\right. x - 1 \left.\right)}\) \(= \frac{x \left(\right. x + 3 \left.\right) - \left(\right. x + 1 \left.\right)}{x \left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}\) \(= \frac{x^{2} + 3 x - x - 1}{x \left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}\) \(= \boxed{\frac{x^{2} + 2 x - 1}{x \left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}}\)

2. \(\frac{x}{x - 1} - \frac{1}{x^{2} - x}\)

\(= \frac{x}{x - 1} - \frac{1}{x \left(\right. x - 1 \left.\right)}\) \(= \frac{x^{2} - 1}{x \left(\right. x - 1 \left.\right)}\) \(= \boxed{\frac{x^{2} - 1}{x \left(\right. x - 1 \left.\right)}}\)

3. \(\frac{x + 1}{x - 5} + \frac{x - 11}{x - 5}\)

\(= \frac{x + 1 + x - 11}{x - 5}\) \(= \frac{2 x - 10}{x - 5}\) \(= \boxed{2}\)

4. \(\frac{2}{x + 3} - \frac{2}{3 - x} - \frac{3 x}{x^{2} - 9}\)

\(= \frac{2}{x + 3} + \frac{2}{x - 3} - \frac{3 x}{\left(\right. x - 3 \left.\right) \left(\right. x + 3 \left.\right)}\) \(= \frac{2 \left(\right. x - 3 \left.\right) + 2 \left(\right. x + 3 \left.\right) - 3 x}{\left(\right. x - 3 \left.\right) \left(\right. x + 3 \left.\right)}\) \(= \frac{x}{x^{2} - 9}\) \(= \boxed{\frac{x}{x^{2} - 9}}\)

5.

\(\frac{2 x^{2} + 1}{x^{3} + 1} - \frac{x - 1}{x^{2} - x + 1} - \frac{1}{x + 1}\) \(= \frac{2 x^{2} + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)} - \frac{\left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)} - \frac{x^{2} - x + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \frac{x \left(\right. x^{2} - x + 1 \left.\right)}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \boxed{\frac{x}{x^{2} - x + 1}}\)

6.

\(\frac{5 - 3 x}{x + 1} - \frac{x - 1}{x^{2} - x + 1} - \frac{1}{x + 1}\) \(= \frac{5 - 3 x - 1}{x + 1} - \frac{x - 1}{x^{2} - x + 1}\) \(= \boxed{\frac{4 - 3 x}{x + 1} - \frac{x - 1}{x^{2} - x + 1}}\)

7. \(\frac{3}{x + 1} - \frac{2 + 3 x}{x^{3} + 1}\)

\(= \frac{3 \left(\right. x^{2} - x + 1 \left.\right) - \left(\right. 2 + 3 x \left.\right)}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \frac{3 x^{2} - 6 x + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \boxed{\frac{3 x^{2} - 6 x + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}}\)

1. \(\frac{x + 3}{x^{2} - 1} - \frac{1}{x^{2} - x}\)

\(\frac{x + 3}{\left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)} - \frac{1}{x \left(\right. x - 1 \left.\right)}\) \(= \frac{x \left(\right. x + 3 \left.\right) - \left(\right. x + 1 \left.\right)}{x \left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}\) \(= \frac{x^{2} + 3 x - x - 1}{x \left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}\) \(= \boxed{\frac{x^{2} + 2 x - 1}{x \left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}}\)

2. \(\frac{x}{x - 1} - \frac{1}{x^{2} - x}\)

\(= \frac{x}{x - 1} - \frac{1}{x \left(\right. x - 1 \left.\right)}\) \(= \frac{x^{2} - 1}{x \left(\right. x - 1 \left.\right)}\) \(= \boxed{\frac{x^{2} - 1}{x \left(\right. x - 1 \left.\right)}}\)

3. \(\frac{x + 1}{x - 5} + \frac{x - 11}{x - 5}\)

\(= \frac{x + 1 + x - 11}{x - 5}\) \(= \frac{2 x - 10}{x - 5}\) \(= \boxed{2}\)

4. \(\frac{2}{x + 3} - \frac{2}{3 - x} - \frac{3 x}{x^{2} - 9}\)

\(= \frac{2}{x + 3} + \frac{2}{x - 3} - \frac{3 x}{\left(\right. x - 3 \left.\right) \left(\right. x + 3 \left.\right)}\) \(= \frac{2 \left(\right. x - 3 \left.\right) + 2 \left(\right. x + 3 \left.\right) - 3 x}{\left(\right. x - 3 \left.\right) \left(\right. x + 3 \left.\right)}\) \(= \frac{x}{x^{2} - 9}\) \(= \boxed{\frac{x}{x^{2} - 9}}\)

5.

\(\frac{2 x^{2} + 1}{x^{3} + 1} - \frac{x - 1}{x^{2} - x + 1} - \frac{1}{x + 1}\) \(= \frac{2 x^{2} + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)} - \frac{\left(\right. x - 1 \left.\right) \left(\right. x + 1 \left.\right)}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)} - \frac{x^{2} - x + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \frac{x \left(\right. x^{2} - x + 1 \left.\right)}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \boxed{\frac{x}{x^{2} - x + 1}}\)

6.

\(\frac{5 - 3 x}{x + 1} - \frac{x - 1}{x^{2} - x + 1} - \frac{1}{x + 1}\) \(= \frac{5 - 3 x - 1}{x + 1} - \frac{x - 1}{x^{2} - x + 1}\) \(= \boxed{\frac{4 - 3 x}{x + 1} - \frac{x - 1}{x^{2} - x + 1}}\)

7. \(\frac{3}{x + 1} - \frac{2 + 3 x}{x^{3} + 1}\)

\(= \frac{3 \left(\right. x^{2} - x + 1 \left.\right) - \left(\right. 2 + 3 x \left.\right)}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \frac{3 x^{2} - 6 x + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}\) \(= \boxed{\frac{3 x^{2} - 6 x + 1}{\left(\right. x + 1 \left.\right) \left(\right. x^{2} - x + 1 \left.\right)}}\)

870

Tạch rồi ạ =)))

Bài giải:

Trang có số nhãn vở là:

5 + 3 = 8 (nhãn vở)

Cả hai bạn có số nhãn vở là:

5 + 8 = 13 (nhãn vở)

Đáp số: 13 nhãn vở

Bài giải:

Số viên bi của Hùng là:

6 + 4 = 10 (viên bi)

Tổng số viên bi của Nam và Hùng là:

6 + 10 = 16 (viên bi)

Đáp số: 16 viên bi

450 + 354 = 804

?????

11-11=0

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