А) 219+(589-130)=219+459=678
б)(678+98)-517=776-517=259
в) 900-(859-214)=900-642=258
г) (800-218)+(326+92)=582+418=1000
x^2=2x-x^2
2x^2=2x
x=0
x=1
S=|x^2-2/3x^3| (0;1)=|1-2/3|=1/3
<span> ( х - 4) (х+ 4)=7
х2 - 16 = 7
х2 = 23
х = </span><span>√23</span>