A car left 42 minutes early than the scheduled time but in order to reach its destination 210 km away in time, it had to slow its usual speed by 10 km/hr. What is the usual speed of the car?

If a = 5 + √6, b = 5 - √6, then what is the value of a² + b²?

If a = 7 + √2, b = 7 - √2, then what is the value of a² + b²?

If x² - y² = 255 and x + y = 17, then find x - y.

If $$2x - \frac{1}{2x} = \frac{10}{3}$$​ and x > 1, then find the value of $$x^2+\frac1{16x^2 }$$​​

The cost of a table exceeds that of a chair by ₹5,000. If the combined price of 16 tables and 14 chairs amounts to ₹2,00,000, determine by what percentage the price of a chair is less than the price of a table.

The difference of squares of two consecutive odd numbers is 56. What is the sum of the two numbers?

If a = 3 + √2, b = 3-√2, then what is the value of a² + b²?

Solve the following system of 3 equations in 3 unknowns.
x - 3z = -5
2x - y + 2z = 16
7x - 3y - 5z = 19

If x+y+z=0, where none of x,y and z is equal to 0 , then find the value of $$\frac{x^2}{yz} + \frac{y^2}{zx} + \frac{z^2}{xy}$$​​