Answer:
The number that goes in place of the question mark is 2.
Step-by-step explanation:
Let's solve it!
3x² + 12x - 24 = 0
First we can factor 3 out of each term:
x² + 4x - 8 = 0
Now we'll add 12 to both sides to complete the square:
x² + 4x + 4 = 12
And finish it off:
(x + 2)² = 12
So the answer to the question is 2
Bonus:
We can also now solve this for x:
(x + 2)² = 12
x = √12 - 2
x = 2√3 - 2
x ≈ 2 × ±1.732 - 2
x ≈ 1.464, -5.464
Answer: y = -5
Substitute in 3 for x.
x - y = 8 Substitution
3 - y = 8 Subtract 3 from both sides
-y = 5 Divide by -1 to both sides
y = -5 Answer!
You can also check your work.
x - y = 8
3 - (-5) = 8
3 + 5 = 8
8 = 8
Answer:
-6
Step-by-step explanation:
We are given that -x-10y=2 is a true equation so by multiplication property of equality, we can multiply everything by -3 on both sides. This gives us 3x+10y=-6
In order to do this, you must first find the "cross product" of these vectors. To do that, we can use several methods. To simplify this first, I suggest you compute:
‹1, -1, 1› × ‹0, 1, 1›
You are interested in vectors orthogonal to the originals, which don't change when you scale them. Using 0,-1,1 is much easier than 6s and 7s.
So what methods are there to compute this? You can review them here (or presumably in your class notes or textbook):
http://en.wikipedia.org/wiki/Cross_produ...
In addition to these methods, sometimes I like to set up:
‹1, -1, 1› • ‹a, b, c› = 0
‹0, 1, 1› • ‹a, b, c› = 0
That is the dot product, and having these dot products equal zero guarantees orthogonality. You can convert that to:
a - b + c = 0
b + c = 0
This is two equations, three unknowns, so you can solve it with one free parameter:
b = -c
a = c - b = -2c
The computation, regardless of method, yields:
‹1, -1, 1› × ‹0, 1, 1› = ‹-2, -1, 1›
The above method, solving equations, works because you'd just plug in c=1 to obtain this solution. However, it is not a unit vector. There will always be two unit vectors (if you find one, then its negative will be the other of course). To find the unit vector, we need to find the magnitude of our vector:
|| ‹-2, -1, 1› || = √( (-2)² + (-1)² + (1)² ) = √( 4 + 1 + 1 ) = √6
Then we divide that vector by its magnitude to yield one solution:
‹ -2/√6 , -1/√6 , 1/√6 ›
And take the negative for the other:
‹ 2/√6 , 1/√6 , -1/√6 ›
Answer:
5.6x-16.9=-0.1
28x/5-16.9=-0.1
28x/5-16.9=-0.1
28x/5-16.9+16.9=-0.1+16.9
28x/5=16.8
x=3
Step-by-step explanation:
