\(\left(17-b\right)^2+b^2=169\Leftrightarrow17^2-2\cdot17\cdot b+b^2+b^2=169\Leftrightarrow2b^2-34b+120=0\)
\(\Leftrightarrow b^2-17b+60=0\Leftrightarrow\left(b-5\right)\left(b-12\right)=0\Leftrightarrow\hept{\begin{cases}b=5\\b=12\end{cases}}\)
Nếu b = 5 cm thì a = 17-5 = 12 cm.Nếu b = 12 cm thì a = 17-12 = 5 cm.