If your question means:
Factorize x² + 3 x - 28 = 0 then first one remark:
3 x = - 4 x + 7 x
So:
x² + 3 x - 28 = x² - 4 x + 7 x - 28
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x² + 3 x - 28 = 0
( x² - 4 x ) + ( 7 x - 28 ) = 0
x ( x - 4 ) + 7 ( x - 4 ) = 0
( x - 4 ) ( x + 7 ) = 0
Factorize ×2+3×-28=0
1 answer