Answer:
see explanation
Step-by-step explanation:
(a)
Consider the factors of the coefficient of the y² term ( - 12) which sum to give the coefficient of the xy- term (- 4)
The factors are - 6 and + 2
since - 6 × 2 = - 12 and - 6 + 2 = - 4, hence
x² - 4xy - 12y² = (x - 6y)(x + 2y)
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(b)
Consider the factors of + 12 which sum to give + 8
The factors are + 2 and + 6, hence
x² + 8x + 12 = (x + 2)(x + 6)
