Completing the square

Use the sliders to change the values of b and c in the quadratic expression x^2+2bx+c.[br]The number of small blue squares represents the value of c. Decide if there are too many or not enough blue squares to complete the outlined red square.
Complete the square for each of these quadratic expressions then use the apllet to check:[br]1. x^2+4x+11[br]2. x^2+6x+5[br]3. x^2+10x+13[br]4. x^2+8x+23[br]5. x^2+2x+7

Information: Completing the square