Question

3) (x - 3)(x + 4) = 0;​

Answer 1

${x}^{2} + 4x - 3x - 12 = 0 \\ {x}^{2} + x - 12 = 0 \\ d = 1 - 4 \times 1 \times ( - 12) = 1 + 48 = 49 = {7}^{2} \\ x1 = \frac{ - 1 + 7}{2 \times 1} = \frac{6}{2} = 3 \\ x2 = \frac{ - 1 - 7}{2 \times 1} = \frac{ - 8}{2} = - 4$

Answer 2

Пошаговое объяснение:

${x}^{2} + 4x - 3x - 12 = 0$

${x}^{2} + x - 12 = 0$

D=1-4×(-12)=1+48=49=7

$x = \frac{ - 1 + 7}{2} = \frac{6}{2} = 3$

$x = \frac{ - 1 - 7}{2} = \frac{ - 8}{2} = - 4$

x=3,x=-4