Question

4y2-28y-72 factorise
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Answer 1

y=9 or

y=2

Step-by-step explanation:

• [tex] {4y}^{2} - 28y - 72 = 0\\ {y }^{2} - 7y - 18 = 0\\ {y}^{2} - 9y + 2y - 18 = 0 \\( {y}^{2} - 9y) + (2y - 18) = 0\\ y(y - 9) + 2(y - 9) = 0 \\ (y - 9)(y + 2) = 0 \\ y - 9 = 0 \: or \: y + 2 = 0 \\ y = 9 \: or \: y = - 2[tex]

Answer 2

Step-by-step explanation:

4y2 - 28y - 72

4 (y2-7y-18)

4 (y2+2y-9y-18)

4 (y×(y+2)-9 (y+2))

4 (y+2)×(y-9) ANSWER