Answer:
The system has infinite solutions described in the set 
Step-by-step explanation:
The augmented matrix of the system is
.
We apply row operations:
1. We add the first row to the second row twice and obtain the matrix ![\left[\begin{array}{cccc}-1&-1&-1&4\\0&-1&-2&10\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D-1%26-1%26-1%264%5C%5C0%26-1%26-2%2610%5Cend%7Barray%7D%5Cright%5D)
2. multiply by -1 the rows of the previous matrix and obtain the matrix
that is the reduced echelon form of the matrix associated to the system.
Now we aply backward substitution:
1. Observe that the reduced echelon form has a free variable, then the system has infinite solutions.
2.

3.
.
Then the set of solutions is 
Answer: 7
Step-by-step explanation:
Here, two chords of the circle is intersecting outside the given circle.
Thus, By the intersecting chord outside the circle theorem,


Hence, the value of x is 7.
√-80 can be factored out, to see which factors can be square rooted. A pair of factors would be 16 and -5, so that would be 4√-5. But, negative numbers cannot be inside a square root. So, √-1 is the same thing as <em>i</em>, or <u>imaginary number</u>. So, the expression equivalent to √-80 is 4<em>i</em>√5.
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Answer:
A. 2x + 15
Step-by-step explanation:
3(2x + 5) - 4x =
= 6x + 15 - 4x
= 2x + 15
Answer: A. 2x + 15
-5(-2)+1
10+1=11
Your answer is C