Let (x₀, y₀) be the solution of the following equations (2x)^(ln 2) = (3y)^(ln 3) ; 3^(ln x) = 2^(ln y). Then x₀ is
(2x)ln2=(3y)ln3
3lnx=2lny
To find x0
(1) 61(2) 31(3) 21(4) 6
1. take ln on both equations
2. set p=ln2, q=ln3, u=lnx, v=lny
3. eliminate v, solve for u, then x=eu
(lnx)(ln3)=(lny)(ln2)
p=ln2,q=ln3,u=lnx,v=lny
qu=pv⋯(A)
(ln2)(ln2+lnx)=(ln3)(ln3+lny)
p(p+u)=q(q+v)⋯(B)
v=pqu
p(p+u)=q(q+pqu)
p2+pu=q2+pq2u
u(p−pq2)=q2−p2
pp2−q2u=−(p2−q2)⟹u=−p
u=lnx=−p=−ln2=ln21
x=eu=21
v=pq(−p)=−q⟹y=31
(2x)ln2=1ln2=1=1ln3=(3y)ln3 ✓
∴ x0=21⇒option (3)