The equations 6x + my + 18 = 0 and 9x + 21y + 27 = 0 have a unique solution. Which of the following statements is definitely true?

If 2x + 3y = 27 and 3x - y = 13, find (x + y).

I. 2p² + 5p + 2 = 0               II. 2q² + 11 q + 14 = 0

I. p² – 5p + 6 = 0                  

II. 36q² = 81

The ratio of roots of an equation

ax²+bx+b = 0 is p : q

Then find, √p/√q + √q/√p + √p/√q ?

If, x - y radic; 3 = 23 and radic; 3x + y = 35

Find the angle between both the lines when they intersect each other.

For which value of m, there is no solution to the equation -

a – b = 5

ma – 4b = 1

If 0.4x + 0.6y = 26 and x - y = 10, find x.

3 pens + 5 pencils = ₹49

4 pens + 3 pencils = ₹47

Find cost of one pen.

Find the area between the lines 18x +12y = 108, 9x  + 6y  = 27, x - axis and y -axis.