Problem: If 4x+2x=1, then x:
Answer Choices:
A. is an integer
B. is fractional
C. is irrational
D. is imaginary
E. may have two different values
Solution:
4x+2x=1∴4x−1=−2x
16x2−10x+1=0∴x=81
x=21 does not satisfy the original equation.
or
Let y=x∴4y2+2y−1=0
y=822,8−42,x=y2=81,21