Question

Ребята помогите решить (3x-3)(5-2x)-x(2-6x). Где x=2/19

Answer 1

Ответ:

-13

Пошаговое объяснение:

1 способ :

$(3x-3)*(5-2x)-x*(2-6x)= \\ \\ = 3x*5+3x*(-2x)-3*5-3*(-2x) - x*2-x*(-6x) = \\ \\ = 15x-6{x}^{2}-15+6x-2x+6{x}^{2}= \\ \\ =x*(15+6-2) -15 = 19x-15$

при x=$\frac{2}{19}$

$19*\frac{2}{19}-15 = \frac{19*2}{19}-15=\frac{38}{19}-15=2-15=-13$

2 способ :

$(3*\frac{2}{19} - 3)*(5-2*\frac{2}{19})-\frac{2}{19}*(2-6*\frac{2}{19}) = \\ \\ =(\frac{6}{19}-3)*(5-\frac{4}{19})-\frac{2}{19}*(2 -\frac{12}{19})= \\ \\ =(\frac{6}{19}-2\frac{19}{19})*(4\frac{19}{19}-\frac{4}{19})-\frac{2}{19}*(1\frac{19}{19}-\frac{12}{19}) = \\ \\ = (\frac{6-57}{19})*(\frac{95-4}{19})-\frac{2}{19}*(\frac{38-12}{19}) = \\ \\ =- \frac{51}{19}*\frac{91}{19}-\frac{2}{19}*\frac{26}{19}=-\frac{4641}{361}-\frac{52}{361}=-\frac{4693}{361}=-\frac{13}{1}=-13$