Question

(x+6)(2x+6)-20 = 0.​

Answer 1

Ответ:

(х+6)(2х+6)-20=0

3х+6х+12х+36-20=0

21х+16=0

21х=0-16

21х=-16

х=-16/21

Answer 2

To solve the quadratic equation $(x+6)(2x+6)-20 = 0$, we can follow these steps:

Step 1: Expand the expressions on the left side of the equation: $(x+6)(2x+6) - 20 = 0$ $2x^2 + 12x + 6x + 36 - 20 = 0$ $2x^2 + 18x + 16 = 0$

Step 2: Set the quadratic equation equal to zero: $2x^2 + 18x + 16 = 0$

Step 3: Solve the quadratic equation. You can use the quadratic formula or factoring to find the solutions. In this case, I'll use the quadratic formula:

The quadratic formula states that for an equation of the form $ax^2 + bx + c = 0$, the solutions are given by: $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

In our equation $2x^2 + 18x + 16 = 0$, we have $a = 2$, $b = 18$, and $c = 16$. Plugging these values into the formula:

$x = \frac{-18 \pm \sqrt{18^2 - 4 \cdot 2 \cdot 16}}{2 \cdot 2}$ $x = \frac{-18 \pm \sqrt{324 - 128}}{4}$ $x = \frac{-18 \pm \sqrt{196}}{4}$ $x = \frac{-18 \pm 14}{4}$

This gives us two possible solutions:

$x_1 = \frac{-18 + 14}{4} = -\frac{4}{4} = -1$ $x_2 = \frac{-18 - 14}{4} = -\frac{32}{4} = -8$

So, the solutions to the equation $(x+6)(2x+6)-20 = 0$ are $x = -1$ and $x = -8$.