If `4/7+2/7=y/21` then `y=`

If (2y)/(7)=(y+3)/(4), then y=

-(4y)/7=-4/9 then y=______

If 4x+5y=83 and (3x)/(2y)=(21)/(22), then y-x=?( a) 3( b) 4 (c) 7 (d) 11

If x + y + z =21 , then the maximum value of (x - 6) (y + 7)(z - 4) is :

If (2x)/3=(4y)/5=(7z)/9 then find the value of (4x+12y-21z)/(3y) .

If 3y + 3 = 7x , then 21y - 49 x =

If x^4+x^2y^2+y^4=21 and x^2+xy+y^2= 7 , then the value of (1/x^2+1/y^2) is : यदि x^4+x^2y^2+y^4=21 तथा x^2+xy+y^2= 7 है, तो (1/x^2+1/y^2) का मान होगा :