Factorize each of the following quadratic polynomials by using the method of completing;

y2 – 7y + 12

Coefficient of y2 = 1


Therefore, we have


y2 – 7y + 12 = y2 – 7y + ()2 – ()2 + 12 [By adding and subtracting ()2]


= (y - )2 – ()2 (Completing the square)


= (y - - ) (y - + )


= (y – 4) (y – 3)


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