\(46+\left(-80\right)+34=\left(46+34\right)-80=80-80=0\)
\(115-\left(-85\right)+35-\left(46+35\right)=115+85+35-46+35\)
\(=\left(115+85\right)+\left(35-35\right)-46=200+0-46=154\)
\(5\left(-9\right).2.\left(-7\right)\left(-2020\right)^0=\left(-45\right)\left(-14\right).1=630\)
\(57\left(49-16\right)+57\left(24-49\right)=57.49+57.16+57.24-57.49\)
\(=57\left(49-49+16+24\right)=57.40=2280\)