Question

`{x}^(2) - 4x = 21`
what are the x intercepts?
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Answer 1

x² - 4x = 21

x² - 4x - 21 = 0

x² - 7x + 3x - 21 = 0

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

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

x + 3 = 0 and x - 7 = 0

x = -3 and x = 7