20. (6 points) Observe the calculation pattern of the following equations:
First row $1+2+3=6$
Second row $3+5+7=15$
Third row $5+8+11=24$
...
The equation in the twelfth row is $\qquad$
20. (6 points) Observe the calculation patterns of the following equations:
First row $1+2+3=6$
Second row $3+5+7=15$
Third row $5+8+11=24$
...
The equation in the twelfth row is $\qquad$ $23+35+47=105$.

【Solution】Solution: From the analysis, we know that the first addend in the twelfth row is $2 \times 12-1=23$, the second addend is $3 \times 12-1=35$, and the third addend is $4 \times 12-1=47$. Therefore, the equation in the twelfth row is $23+35+47=105$. Hence, the answer is: $23+35+47=105$.