<span>0,4c^2d(−4c^2−cd−d)=-1.6c^4d-0.4c^3d^2-0.4c^2d^2</span>
4/(√8)
=(4*√8)/(√8*√8)=(4√8)/8=√8/2=2√2/2=√2
D=a2-a1=a3-a2=a4-a3=-------. d=11-7=4, d=4
a18=a1+17.4=7+68=75
s18=18/2(a1+a18)=9(7+75)=9.82=738
s18=738
- 2X^2 = - 8
X^2 = 4
X1 = 2
X2 = - 2
Ответ ( 2 ; - 8 ) ; ( - 2 ; - 8 )