\(a.10-\left[12-\left(-9-1\right)\right]\)
\(=10-12+9+1\)
\(=8\)
\(a,10-\left[12-\left(-9-1\right)\right]\)
\(=10-\left[12+9+1\right]\)
\(=10-22=-12\)
\(b,271-\left[\left(-43\right)+27-\left(-17\right)\right]\)
\(=271-\left[-43+27+17\right]\)
\(=271-\left[1\right]\)
\(=270\)
\(c,-144-\left[29-144-144\right]\)
\(=-144-29+144+144\)
\(=144-29=115\)