Solve using the factoring method: x2 + 4x - 21 = 0

1 answer:

6 0

Answer:

x² + 4x - 21 = 0

x² + 7x - 3x - 21 = 0

x ( x + 7 ) -3 ( x + 7 ) = 0

( x - 3 ) ( x + 7 ) = 0

∴ x - 3 = 0 or x + 7 = 0

x = 0 + 3 x = 0 - 7

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