factor completely ; 49s^2+9-42s?
回答 (3)
2008-09-24 7:39 am
✔ 最佳答案
(7s-3)(7s-3)
2008-09-24 4:09 pm
49s^2 + 9 - 42s
= 49s^2 - 42s + 9
= 49s^2 - 21s - 21s + 9
= (49s^2 - 21s) - (21s - 9)
= 7s(7s - 3) - 3(7s - 3)
= (7s - 3)(7s - 3)
= (7s - 3)^2
= 49s^2 - 42s + 9
= 49s^2 - 21s - 21s + 9
= (49s^2 - 21s) - (21s - 9)
= 7s(7s - 3) - 3(7s - 3)
= (7s - 3)(7s - 3)
= (7s - 3)^2
2008-09-24 2:38 pm
( 7 s - 3 )( 7 s - 3 ) = ( 7 s - 3 ) ²
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