Question

lg(4^x+9)=lg5+lg(2^x+1
)

Answer 1

lg(4^x +9)=lg[5(2^x +1)]
2^2x -5*2^x+9-5=0
2^2x -5*2^x+4=02^x=a
a²-5a+4=0
a1+a2=5 U a1*a2=4
a1=1⇒2^x=1⇒x=0
a2=4⇒2^x=4⇒x=2