-20×(-2^2)=-20×4=-80
Ответ: -80
у=1,5х
Решение приведено во вложенном файле, сейчас всё поясню.
5χ+3χ=180
<span>8χ=180</span>
<span>χ=180:8</span>
<span>x=22.5</span>
<span>5·22.5=112.5</span>
<span>3·22.5=67.5</span>
<span>BOC=112.5° ABC=67.5° </span>
7)9,8 ;8)300;9)1х;10)02х
вроде так удачи
(1/3*1/2m+1/3*(-3)-m*1/2m-m*(-3)
(1/3*1/2m+1*(-1)-m*1/2m-m*(-3)
(m/2*3+1*(-1)-m*1/2m-m*(-3)
1/6m+1*(-a)-m=1/2m-m*(-3)
(1/6m-1-m*1/2m-m*(-3)
(1/6m-1-1/2m^2-m*(-3)
(1/6m-1-1/2m^2+3m)
(-1/2m^2+1/6m+3m-1)
(-1/2m^2+1/6m+3m*6/6-1)
(-1/2m^2+1/6m+18m/6-1)
(-1/2m^2+1/6(m+18m)-1)
(-1/2m^2+19m/6-1)
-1/2m^2+19m/6-1 ответ!