Tính -18+(-19)+27

1)tính

a)\(-17+\left(-19\right)+25\)

\(=-17-19+25\)

\(=-\left(17+19\right)+25\)

\(=-36+25\)

\(=-\left(36-25\right)\)

\(=-11\)

b)\(-26+\left(-25\right)-18\)

\(=-26-25-18\)

\(=-\left(26+25\right)-18\)

\(=-51-18\)

​\(=-\left(51+18\right)\)​

\(=-69\)

c)\(35-\left(-19\right)-19-8\)

\(=35+19-19-8\)

\(=35+\left(19-19\right)-8\)

\(=35+0-8\)

\(=35-8\)

\(=27\)

d)\(1963-\left(-180\right)-1990\)

\(=1963+180-1990\)

\(=2143-1990\)

\(=153\)

2)Tìm x thuộc z biết

a)\(x-\left(-18\right)=25+\left(-17\right)\)

\(\Leftrightarrow x+18=25-17\)

\(\Leftrightarrow x+18=8\)

\(\Leftrightarrow x=8-18\)

\(\Leftrightarrow x=-10\)

Vậy x=-10

b)\(x-28=-27-30\)

\(\Leftrightarrow x-28=-\left(27+30\right)\)

\(\Leftrightarrow x-28=-57\)

\(\Leftrightarrow x=-57+28\)

\(\Leftrightarrow x=-\left(57-28\right)\)

\(\Leftrightarrow x=-29\)

Vậy x=-29

c)\(35-\left(-x\right)=27-18-\left(-8\right)\)

\(\Leftrightarrow35+x=27-18+8\)

\(\Leftrightarrow35+x=9+8\)

\(\Leftrightarrow35+x=17\)

\(\Leftrightarrow x=17-35\)

\(\Leftrightarrow x=-18\)

Vậy x=-18

d)\(40+\left(-x\right)=35-\left(-27\right)\)

\(\Leftrightarrow40-x=35+27\)

\(\Leftrightarrow40-x=62\)

\(\Leftrightarrow x=40-62\)

\(\Leftrightarrow x=-22\)

Vậy x=-22

1)tính

a)-17+(-19)+25=

b)-26+(-25)-18=

c)35-(-19)-19-8=

d)1963-(-180)-1990

2)Tìm x thuộc z biết

a)x-(-18)=25+(-17)

b)x-28=-27-30

c)35-(-x)=27-17-(-8)

d)40+(-x)=35-(-27)

nhanh nha các bạn để mai mình đi học

1)tính

a)\(-18+\left(-19\right)+27\)

\(=-18-19+27\)

\(=-\left(18+19\right)+27\)

\(=-37+27\)

\(=-\left(37-27\right)\)

\(=-10\)

b)\(-198-194+286\)

\(=-\left(198+194\right)+286\)

\(=-392+286\)

\(=-\left(392-286\right)\)

\(=-6\)

c)\(-19-\left(-17\right)\)

\(=-19+17\)

\(=-\left(19-17\right)\)

\(=-2\)

d)\(-48+\left(-47\right)-\left(-15\right)\)

\(=-48-47+15\)

\(=-\left(48+47\right)+15\)

\(=-95+15\)

\(=-\left(95-15\right)\)

\(=-80\)

e)\(23-\left(-16\right)+\left(-80\right)\)

\(=23+16-80\)

\(=39-80\)

\(=-80+39\)

\(=-\left(80-39\right)\)

\(=-41\)

f)\(99-\left(-99\right)-198\)

\(=99+99-198\)

\(=198-198\)

\(=0\)