Question

Решите уравнение: a^2-8a-9=0

Answer 1

a^2-8a-9=0

x^2+x-9x-9=0

x*(x+1)-9(x+1)=0

(x+1)*(x-9)=0

Ответы x=-1 x=9

Answer 2

Это квадратное уравнение и оно решается по формулам. Я уверена, что у меня всё правильно. Я люблю решать уравнения

Answer 3

To solve the quadratic equation $a^2 - 8a - 9 = 0$, we can use the quadratic formula, which is given by:

$a = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

where $a$, $b$, and $c$ are coefficients of the quadratic equation $ax^2 + bx + c = 0$.

For our equation $a^2 - 8a - 9 = 0$, we have $a = 1$, $b = -8$, and $c = -9$.

Now, plug these values into the quadratic formula:

$a = \frac{-(-8) \pm \sqrt{(-8)^2 - 4 \cdot 1 \cdot (-9)}}{2 \cdot 1}$

$a = \frac{8 \pm \sqrt{64 + 36}}{2}$

$a = \frac{8 \pm \sqrt{100}}{2}$

$a = \frac{8 \pm 10}{2}$

Now, we have two solutions for $a$:

1. When $a = \frac{8 + 10}{2} = \frac{18}{2} = 9$
2. When $a = \frac{8 - 10}{2} = \frac{-2}{2} = -1$

So, the solutions to the equation $a^2 - 8a - 9 = 0$ are $a = 9$ and $a = -1$.