Tolong dibantu klo bisa pakai cara nya besok mau dikumpul, terimakasih :)

garis 9x + by = 1 melalui titik (1,2) maka
9x + by = 1
9(1) + b(2) = 1
9 + 2b = 1
2b = -8
b = -4

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garis (b + 1)x + 7y = -8 melalui (2,-2)
(b + 1)x + 7y = -8
(b + 1)(2) + 7(-2) = -8
2b + 2 - 14 = -8
2b = -8 - 12
2b = -20
b = -10