Răspuns:
b) 2×2³×2⁵×...×2¹⁷=2^(1+3+5+...+17)=2⁸¹=2^9x
x=81:9=9
c)2^2x ×2^4x × 2^6x ×...×2^20x=2^(2x+4x+6x+...20x)
=2^(2x ×(1+2+3+...+10))=2^110x=1024²²
1024=2^10=> 2^110x=2^(10×22)=> 110x=220
x=220:110=2
d)3^(x+3x+5x+...21x)=3^121x=3^(11×22) => 121x= 11×(11×2)
x= 121×2:121=2
OBS
1+3+5+...+2n-1=n²
