If `7:9 :: 8: x:: 6:2` find the value of `x`

If x-y=7\ a n d\ x y=9, find the value of x^2+y^2

If x=5, find the value of : 6-7x^(2)

If the ratio between 8 and 11 is the same as the ratio of 2x - y to x + 2y , find the value of (7x)/(9y) .

If 2x+3y=8 and x y=2 , find the value of 4x^2+9y^2

If 3x+2y=12 and x y=6, find the value of 9x^2+4y^2

If 3x+2y=12 and x y=6 , find the value of 9x^2+4y^2

If 3x-7y=10\ and x y=-1, find the value of 9x^2+49 y^2

If |x^2-7|le 9 then find the values of x

If the mean of 4, 6, x, 9, 10, 5 is 7, find the value of x.

If x=sqrt(3) find the value of 2x^2-8x+7.