a)17.85+15.17+(-120)
=17.(85+15)+(-120)
=17.100+(-120)
=1700+(-120)
=1580
a: \(17\cdot85+15\cdot17+\left(-120\right)\)
\(=17\left(85+15\right)-120\)
\(=17\cdot100-120=1700-120=1580\)
b: \(75-\left(-3\cdot5^2+4\cdot2^3\right)\)
\(=75+3\cdot5^2-4\cdot2^3\)
\(=75+3\cdot25-4\cdot8\)
\(=75+75-32=150-32=118\)
c: \(75-\left(3\cdot5^2-4\cdot2^3\right)\)
\(=75-3\cdot25+4\cdot8\)
\(=75-75+32=32\)
d: \(\left(-15\right)+14+\left(-85\right)\)
\(=\left(-15-85\right)+14\)
=-100+14
=-86
e: \(28\cdot76+28\cdot24\)
\(=28\left(76+24\right)\)
\(=28\cdot100=2800\)
f: \(29\left(19-13\right)-19\left(29-13\right)\)
\(=29\cdot19-29\cdot13-19\cdot29+19\cdot13\)
\(=-29\cdot13+19\cdot13\)
\(=13\left(-29+19\right)=13\cdot\left(-10\right)=-130\)
