Question

answer the questions.............

Answer 1

6sol :given:3/x+4/y=18     -I
          5/x+6/y=28     -II
let 1/x=a,1/y=b
eq. I*5-eq.II*3
     15a+20b=90        -III
     15a+18b=84        -IV
    -      -       =-        (symbols change)
             2b=6
     b=6/2=3 
so y=1/3 
a=2    (subs. b=3 in eq.I)
    x=1/2 
x+y=1/3+1/2=5/6 
so option is A

7sol:given= 3a2-2x-1/3 
       now v have 9a2(square)-6x-1 =0     (solve the above eq by lcm )
      b2-root 4ac 
    subst. the above values in the formula. 
   then v get not real roots. (c)
10sol (d) 4Q