Jawabanmu

2014-08-02T11:43:26+07:00
4 (7y²+6y-5) -5 (4y²-4y+8)
= (28y² + 24y - 20) - (20y² + 20y - 40)
= 28y² + 24y - 20 - 20y² - 20y + 40
= 28y²- 20y² + 24y- 20y - 20 + 40
= 8y² + 4y + 20
maaf kalo salah atau kurang teliti :)
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