Объяснение:
y(x) = -8х +1;
y(a+1) = -8(a+1) +1=-8a-8+1=-8a-7;
y(a) = -8a +1;
y(a+1)-y(a)=-8a-7-(-8a +1)=-8a-7+8a -1=-8;
y(a+1)-y(a)=-8
