4.03  Quadratic Formula

Intermediate Algebra: One Step at a Time.  Page 323 -331   #10, 25, 26

NEW PROBLEMS:  #10, 25, 26

Dr. Robert J. Rapalje

Seminole Community College

Sanford, FL  32773

p. 326:  #10.         

Solution:  Of course you probably recognize that this problem can be solved by factoring, and indeed this is the easiest way to solve it.  However, you are asked to solve this page of problems by the Quadratic Formula as a means of confirming the method of Quadratic Formula. 

Remember that the solution to the quadratic equation:   

                                               is given by the formula:

In the equation:  

Check by factoring: 

p. 330.  # 25.        

This is a quadratic equation, so the first step is to set it equal to zero, preferably with a positive   term.  This can be done by moving everything to the right side, by adding and  to each side.

This quadratic equation cannot be solved by factoring, so in this case, the quadratic formula is the best choice of methods.

Remember that the solution to the quadratic equation:   

                                               is given by the formula:

In the equation:  

Factor out the common factor of 2 in the numerator, and reduce the fraction.

p. 330.  # 26.   

The first step is to multiply out the parentheses, and notice that it is a quadratic equation.  When you see this, you might as well go ahead and set it equal to zero by adding +5 to each side of the equation.

This quadratic equation cannot be solved by factoring, so the quadratic formula is the best method.

Remember that the solution to the quadratic equation:   

                                               is given by the formula:

In the equation:               

Factor out the common factor of 2 in the numerator, and reduce the fraction.

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