Question 108230
a) let z=9^x ... z^2=2z+3 ... z^2-2z-3=0 ... (z-3)(z+1)=0 ... z=3, z=-1
 ... the negative value is not realistic ... 3=9^x ... x=1/2


b) multiplying by 3^x gives 3*(3^x)^2+9=28(3^x) ... the method of solution is similar to a)