1003044703
Level:
B
The following exponential equation has two solutions \( x_1 \) and \( x_2 \). Solution \( x_1 \) is a prime number. Find the sum of \( 3x_1 \) and \( 2x_2 \).
\[ 3^{3-x}\cdot4^{x-1}+3^x\cdot4^{2-x}=21 \]
\( 8 \)
\( 7 \)
\( 0 \)
\( 3 \)