`9x^2+12xy`

If cos^-1 frac {x}{2} + cos^-1 frac {y}{3}= theta , prove that : 9x^2-12 xy cos theta + 4 y^2= 36 sin^2theta .

Factorise : 4x^(2) + 9y^(2) + 16z^(2) +12xy - 24yz - 16xz

Reduce the following ratios into their lowest from and find their inverse ratios 9xy : 12xy . (Where x and y are not zero).

Solve (9x^(2) + 8xy-4)-(7x^(2) -2xy +2) .

Factorise the following expression: ( i) 4x^(2) +9y^(2) +25z^(2) +12xy +30yz + 20zx (ii) 25x^(2) +4y^(2) +9z^(2) -20 xy +12yz - 30zx

Reduce the following into their lowest form and lets find their inverse ratios. 9xy : 12xy

If cos ^(-1) ""(x)/(2) + cos ^(-1) "" (y)/(3) = theta, then prove that 9x ^(2) - 12 xy cos theta + 4y ^(2) = 36 sin ^(2) theta

Factorise: 4x ^(2) + 9y^(2) + 12 xy