Question

Решите уравнение: .(х²+7х)-4х-28=0 ​

Answer 1

Ответ:

$x_{1} = 7 \\ x_{2} = 4$

Объяснение:

$( {x}^{2} + 7x) - 4x - 28 = 0 \\ x \times (x + 7) - 4 \times (x + 7) = 0 \\ (x + 7) \times (x - 4) = 0$

х+7=0 или х-4=0

$x_{1} = - 7 \\ x_{2} = 4$

Answer 2

$(x^{2} +7x)-4x-28=0\\\\x^{2}+7x-4x-28=0\\\\x^{2} +3x-28=0\\\\D=3^{2}-4\cdot(-28)=9+112=121=11^{2}\\\\x_{1} =\frac{-3-11}{2}=-7\\\\x_{2}=\frac{-3+11}{2}=4\\\\Otvet:\boxed{-7 \ ; \ 4}$