bantu nomor 2-7 kawan

2. =−6p2 + 9q2+ −16p2 + 25q2
=(−6p2 + −16p2) + (9q2 + 25q2)
=−22p2+34q2 (b)

5. =9x2 + 12xy + 4y2 + −12x2 + 60xy + −75y2
=(9x2 + −12x2) + (12xy + 60xy) + (4y2 + −75y2)
=−3x2 + 72xy −71y2 (b)

6. (2a + 3b − 4c)2
=(2a + 3b + −4c)(2a + 3b + −4c)
=(2a)(2a) + (2a)(3b) + (2a)(−4c) + (3b)(2a) + (3b)(3b) + (3b)(−4c) + (−4c)(2a) + (−4c)(3b) + (−4c)(−4c)
=4a2 + 6ab - 8ac + 6ab + 9b2 − 12bc − 8ac − 12bc + 16c2
=4a2 + 12ab − 16ac + 9b2 − 24bc + 16c2