Question

(3x+1)(5х-1)=(5х+2)(3х-4)-7х

Answer 1

Ответ:

$x = -\dfrac{7}{23}$

Объяснение:

$(3x+1)\cdot (5x-1) = (5x+2)\cdot (3x-4) - 7x$

$3x \cdot 5x + 3x \cdot (-1) + 1 \cdot 5x + 1 \cdot (-1) = 5x \cdot 3x + 5x \cdot (-4) + 2 \cdot 3x + 2 \cdot (-4) - 7x$

$15x^2 - 3x + 5x - 1 = 15x^2 -20x + 6x - 8 - 7x$

$15x^2 - 15x^2 -3x + 5x + 20x - 6x + 7x - 1 + 8 = 0$

$2x + 20x + x +7=0$

$23x + 7 = 0$

$23x = -7$

$x = -\dfrac{7}{23}$