Question

Решите пожалуйста уровнене x^2+4x-21=0

Answer 1

Решение смотрите во вложении.

Answer 2

D =4^2-4*1*(-21)=16+84=100
x1=-4+10/2=6/2=3
x2=-4-10/4=-14:2=-7

Answer 3

I can help you solve the equation $x^2+4x-21=0$ in detail. The equation is quadratic, which means it has the form $ax^2+bx+c=0$. To find the roots of the equation, we can use the quadratic formula:

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

In this case, $a=1$, $b=4$, and $c=-21$. Plugging these values into the formula, we get:

$$x = \frac{-4 \pm \sqrt{4^2-4(1)(-21)}}{2(1)}$$

Simplifying, we get:

$$x = \frac{-4 \pm \sqrt{100}}{2}$$

$$x = \frac{-4 \pm 10}{2}$$

Therefore, the equation has two roots:

$$x_1 = \frac{-4 + 10}{2} = 3$$

$$x_2 = \frac{-4 - 10}{2} = -7$$

You can check that these values satisfy the original equation by plugging them in. For more information on how to solve quadratic equations, you can visit [this website](https://ru.symbolab.com/solver/equation-calculator). I hope this helps.