Question : If $x^2+\frac{1}{x^2}=98$, then the value of $x+\frac{1}{x}$ is:
Option 1: 10
Option 2: 8
Option 3: 7
Option 4: 9
Correct Answer: 10
Solution : $x^2+\frac{1}{x^2}=98$ $⇒x^2+\frac{1}{x^2}+2=100$ $⇒x^2+\frac{1}{x^2}+2×x×\frac{1}{x}=100$ $⇒(x+\frac{1}{x})^2=10^2$ $\therefore x+\frac{1}{x}=10$ Hence, the correct answer is 10.
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Question : If $\frac{x}{4 y}=\frac{3}{4}$ then, the value of $\frac{2 x+3 y}{x–2 y}$ is:
Option 1: 7
Option 2: 9
Option 3: 6
Option 4: 8
Question : If $\frac{x^{2}-x+1}{x^{2}+x+1}=\frac{2}{3}$, then the value of $\left (x+\frac{1}{x} \right)$ is:
Option 1: 4
Option 2: 5
Question : If $x^2+\frac{1}{x^2}=\frac{7}{4}$ for $x>0$, what is the value of $(x^3+\frac{1}{x^3})$?
Option 1: $\frac{3\sqrt{3}}{5}$
Option 2: $\frac{3\sqrt{15}}{5}$
Option 3: $\frac{3\sqrt{15}}{8}$
Option 4: $\frac{3\sqrt{5}}{8}$
Question : If $x^2-3 x+1=0$, then the value of $\left(x^4+\frac{1}{x^2}\right) \div\left(x^2+1\right)$ is:
Option 1: 5
Option 2: 6
Option 3: 9
Option 4: 7
Question : If the 9-digit number $72 x 8431y 4$ is divisible by 36, what is the value of $(\frac{x}{y}-\frac{y}{x})$ for the smallest possible value of $y$, given that $x$ and $y$ are natural numbers?
Option 1: $1 \frac{5}{7}$
Option 2: $2 \frac{1}{10}$
Option 3: $1 \frac{2}{5}$
Option 4: $2 \frac{9}{10}$
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