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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