



 
We have two responses for you Alberto, Think about trying to plot the graph of f(x) = ax^{2} + bx + c. What can you say about the point (1, f(1))? Is it above the xaxis or below the xaxis? What about (0, f(0))? Since ax^{2} + bx + c has no real roots the graph of f(x) = ax^{2} + bx + c never crosses the xaxis. Harley
Two hints: what do you know about b^2  4ac from the first statement? consider the second statement separately for b>0 and b<0. Does one of these yield a contradiction with a little work? Good Hunting! RD  


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