Solve for x 9x123x110 a xln11x0 b x1 c xlog311x1 d xlog311x0
Solve for x: 9^x123^x+11=0.
a) x=ln(11),x=0
b) x=1
c) x=log3(11),x=1
d) x=log3(11),x=0
e) x=ln(11)
f) None of the above.
Solution
9^x123^x+11=0
substitute 3^x = y ;9^x =( 3^x)^2 = y^2
So, y^2 -12y +11=0
y^2 -11y -y +11 =0
y(y-11) -1(y -11) =0
(y -1)( y -11) =0
y =1 ; 3^x =1
x =0
y = 11 ; 3^x =11
xln3 = ln11
x = ln(11)/ln3 = ln3(11)
Solution x =0 , ln3(11)
Option d
