146k views
3 votes
If x2 + 6x + 8 = 0 , then x could equal which of the following?

User Ygautomo
by
6.0k points

2 Answers

2 votes

Answer:

x is -2 and -4

User Ori Dar
by
6.5k points
4 votes

Answer:

x = -4 , -2

Explanation:

I am assuming "x2" is x^2. If the equation is x^2 + 6x + 8 = 0, then you first have to factor the equation x^2 + 6 + 8.

In order to do that, you would have to find the multiples of 1 (from x) and 8.

We can see that 1 * 1 is 1, so that is the only pair that would work for the problem. 4 * 2 is 8, but 8 * 1 is also 8. So, which set of numbers do we have to choose? It's actually really simple. You multiply the first set of numbers (1 and 1) with one of the sets from 8 ( 4 and 2 or 8 and 1). Then when you are finished multiplying them together, you add them together to see if they equal to the number in the middle (6x). So 1(x) * 4 is 4x, and 1(x) * 2 is 2x, and when we add the numbers together, we get 6x, which is the middle number, so therefore, 4 and 2 is the correct set of numbers, not 8 and 1, because if we multiply and add those together, we get 7x, not 6x.

After doing that, you have to put them like this:

(x + 4)(x + 2)

This is so when you multiply them together, you get the starting equation. But we have to solve for x. In order to do that, we have to plug that into the equation we started off with.

(x + 4)(x + 2)=0

Now we have to make x + 4 and x + 2 equal to 0, so x is -4 and -2. There are two correct answers. Hope this helps :)

User Rukmal Dias
by
7.3k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.