Question

3. x2 - 4x – 21 by spltting the middle term​

Answer 1

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Answer 2

SOLUTION

${x}^{2} - 4x - 21 \\ = > {x}^{2} - 7x + 3x - 21 = 0 \\ = > x(x - 7) + 3(x - 7) = 0 \\ = > (x - 7) \: (x + 3) = 0 \\ = > x - 7 = 0 \: \: \: or \: \: \: \: x + 3 = 0 \\ = > x = 7 \: \: or \: \: \: x = - 3$

hope it helps ☺️