2y - (y-(y-(y-7))) = 2y - (y - 7) = y + 7
1. d= -2
an=a1+(n-1)d
a1=0,
a2=0+d= -2
a3=0+2d= -4
a4=0+3d= -6
2. b3=10
q=2
bn=b1*q^(n-1)
b1=bn/q^(n-1)=b3/q^2=10/4=2,5
b2=b1*q=2,5*2=5
b3=5*2=10
b4=b3*2=20
b5=b4*q=20*2=40
f⁾(x) =(x² +3х+1)⁾ =2х²⁻¹+3*1+0 = 2х+3
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