X2+2x+8=0 solve by completing the square

x = i sqrt(7) - 1 or x = -i sqrt(7) - 1

Step-by-step explanation:

Solve for x:

x^2 + 2 x + 8 = 0

Subtract 8 from both sides:

x^2 + 2 x = -8

Add 1 to both sides:

x^2 + 2 x + 1 = -7

Write the left hand side as a square:

(x + 1)^2 = -7

Take the square root of both sides:

x + 1 = i sqrt(7) or x + 1 = -i sqrt(7)

Subtract 1 from both sides:

x = i sqrt(7) - 1 or x + 1 = -i sqrt(7)

Subtract 1 from both sides:

 x = i sqrt(7) - 1 or x = -i sqrt(7) - 1

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.

the answer is:

the correct option is the option b.

to calculate the surface area of the right cylinder, we need to use the following formula:

from the picture we know that:

so, substituting and calculting we have:

hence, we have that the correct option is the option b.

have a nice day!