Question

i need help with math.

Answer 1

sure, what's up?

Answer 2

wait no, i apologize it is x^2+15x=-56

Answer 3

Solving typically means well, setting an equation equal to something and finding the variable missing. Doh! Just saw your question, one min

Answer 4

ok, you want to add 56 to both sides and then factor

Answer 5

factoring is hard for me though.

Answer 6

Ok first step in finding this "un-distribute", if you will, the x

Answer 7

See how this works?
\[x^2 + 15x --> x ( x + 15 )\]

Answer 8

yes

Answer 9

Great! You can do it in reverse, and that's called "distributing" (aka. distributive property).

Now you have two roots ("root" is the proper word for the solution here)

set x = to -56
set x + 15 = to -56

Answer 10

Can you identify your two roots now? (and if there's an x-squared like this you should expect two roots, two answers, and either-or kind of thing)

Answer 11

@agentx5 you only factor is the equation is set equal to 0

Answer 12

but you have the right idea.
so for this, you get x^2 -15x +56 = 0
then what you do if find two numbers that add up to -15 and multiply together to 56.
those numbers are -7 and -8
makes sense so far?

Answer 13

Perhaps I need to clarify in steps...

If you're starting from here:
x^2+15 x = -56

Add 225/4 to both sides:
x^2+15 x+225/4 = 1/4

Factor the left hand side:
(x+15/2)^2 = 1/4

Take the square root of both sides, remember you technically need to put an absolute value here (abs()):
abs(x+15/2) = 1/2

Eliminate the absolute value (we've got positive roots here):
x+15/2 = -1/2 or x+15/2 = 1/2

Subtract 15/2 from both sides:
x = -8 or x+15/2 = 1/2

Subtract 15/2 from both sides:
x = -8 or x = -7

If anyone wants to check my algebra please feel free to. :-)

Answer 14

@agentx5 why would you do that?!
just take the 56 to the other side!

Answer 15

I would presume the topic started probable started from being asked to solve:
\[ x^2 + 15x + 56 = 0 ]\

@cerezas , There's more than one way to solve this. And I'm getting there, hold on ok?

Answer 16

completing the square is vastly more complicated here than just factoring or even plugging into the quadratic formula.
i just think that seems like forcing completing the square into something that doesn't need it

Answer 17

The simpler method, miranda, is to factor the two apart by moving -56 over to the other side by adding +56 to both sides.
\[x^2 + 15x + 56 = 0\]

You can now factor it:
\[(x+7)(x+8) = 0\]

And solve each one individually as a tiny equation:
x+7 = 0
x+8 = 0

-7 or -8

Answer 18

When looking for factors a tip that can help is to first look at the x-squared. That's got to be x * x.

Then look at the 56? What are two things that can multiply together to form 56, and can add or subtract to form 15? The answer? +7 and +8

7*8 = 56
7+8 = 15

\[ax^2 + bx + c\]
a = (1)
b = (15)
c = (56)
\[x^2+15x+56\]


Does that help you understand what's going on better miranda? :-)