Jika (3c-7)(3x+7)=ax^2+bx+c,maka nilai a+b+c adalah... A.-58 B.-40 C.48 D.58

[tex](3x - 7)(3x + 7) = ax {}^{2} + bx + c \\ 9x {}^{2} - 49 = ax {}^{2} + bx + c \\ 9x {}^{2} = ax {}^{2} \\ a = 9 \\ bx = 0 \\ b = 0 \\ - 49 = c \\ c = - 49 \\ a +b + c = 9 + 0 - 49 = - 40[/tex]
jawab : B
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