Question

(y²+7y-18) +(y+9) can be factorised as
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Answer 1

Step-by-step explanation:

$= {y}^{2} + 7y - 18 + y + 9 \\ = {y}^{2} + 8y - 9 \\ = {y}^{2} + (9 - 1)y - 9 \\ = {y}^{2} + 9y - y - 9 \\ = y(y + 9) - 1(y + 9) \\ = (y + 9)(y - 1)$