Question
Factorise the following:$5 - 4(a - b) - 12(a - b)^2$
✓
Answer
$5 - 4(a - b) - 12(a - b)^2$
$= 5 - 10(a - b) + 6(a - b) - 12(a - b)^2$
$= 5[1 - 2(a - b)] + 6(a - b)[1 - 2(a - b)]$
$= [5 + 6(a - b)][1 - 2(a - b)]$
$= (5 + 6a - 6b)(1 - 2a + 2b).$
$= 5 - 10(a - b) + 6(a - b) - 12(a - b)^2$
$= 5[1 - 2(a - b)] + 6(a - b)[1 - 2(a - b)]$
$= [5 + 6(a - b)][1 - 2(a - b)]$
$= (5 + 6a - 6b)(1 - 2a + 2b).$
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