1條f4數-_-

芒果:)

solve the equation:

2^ (2x+3) +2^(x+1) = 2^4

[adore]

john24d2003

2^ (2x+3) +2^(x+1) = 2^4
2^2x‧2^3+2^x‧2^1=2^4
8(2^x)^2+2(2^x)-16=0
2次方程禁機...
2^x=1.29 or  2^x=-1.54(rej.)
xlog2=log1.29
      x=0.373

firefighter628

X=1.29