На Паскале:
var y,x:real;
begin
writeln('Введите значение x: ');
readln(x);
if x<=-5 then</p>
writeln('y = ',(1/4)*x+2/3)
else
if (x>-5) and (x<8) then </p>
writeln('y = ',3*sqr(x)*x-4*sqr(x)+5*x)
else
if x>=8 then
writeln('y = ',5*sqr(x)-4*x+1);
end.