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I don’t understand this problem

I don’t understand this problem-example-1
User Barjavel
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1 Answer

4 votes

z^2 - z - 72

z^2 - 9z + 8z - 72

Step 1: 72 = 9 * 8 and when we subtract -9+8 = -1 and that's how I went from z^2 - z - 72 to z^2 - 9z + 8z - 72.


Step 2: Taking out common value from first and second; and third and fourth.

z^2 - 9z = z(z - 9)

8z - 72 = 8 (z - 9)

z^2 - 9x + 8x - 72

z(z-9) + 8(z-9)

(z-9) (z+8)

User Lost In Alabama
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