If xy = -30 and x2 + y2 = 61, then find the value of (x + y).

The average revenues of 13 consecutive years of a company is Rs 82 lakhs. If the average of first 7 years is Rs 77 lakhs and that of last 7 years is Rs 89 lakhs, find the revenue for the 7th year.

If 3x - 10 = -(2x + 5), then the numerical value of (x - 4)3 is

The area of an equilateral triangle is 9√3 sq cm, find its perimeter?

Find measure of central angle of the arc whose length is 22 cm and radius of the circle is 28 cm?

To travel 708 km, an Express train takes 6 hours more than Rajdhani train. If however, the speed of the Express train is doubled, it takes 3 hours less than Rajdhani train. What is the speed of Rajdhani train?

If 5A = 13B = 7C; find the value of A : B : C.

P(3,1) and R(-7,5) are vertices of a rhombus PQRS. What is the equation of diagonal QS?