Question

Rez. ec si inecuatiil :
a ) 2 la puterea x+1 x 2 la puterea 3x-5 = 16
b ) 3 la puterea 2x-1 x 3 la puterea 2x+1 = 81
c) 5 la puterea 2x+1 x s la puterea x+7 = 25
15 puncte, e suficient.

Answer 1

a)$2^{x+1}*2 ^{3x-5}= 2^{4} \ \textless \ =\ \textgreater \ x+1+3x-5=4 =\ \textgreater \ x=2$

b)$3^{2x-1}* 3^{2x+1}=3^4 \ \textless \ =\ \textgreater \ 2x-1+2x+1=4 =\ \textgreater \ x=1$

c)$5^{2x+1}* 5^{x+7}=5^2 \ \textless \ =\ \textgreater \ 2x+1+x+7=2 =\ \textgreater \ 3x=-6=\ \textgreater \ x=-2$