I think the root of "3x + 1 = 7" is 2...
The best way to answer this item is to use the Substitution method. Substitute the value of y from the first equation to the y of the second equation such that the second equation becomes,
-4x + 3(x - 4) = -3
Simplifying the equation,
-x = 9
Dividing both sides by -1 gives an answer of,
<em>x = -9</em>
Then, substitute the value of x in the first equation.
y = -9 - 4
<em> y = -13</em>
The answer to this item is letter B.
Since there is two negative signs in the original equation, you need two negative signs in the equivalent one as well.
Because one of the negatives if before the fraction, it doesn't matter if the second negative is on the 13 or on the 12.
The answer is A.
Using relations in a right triangle, considering c as the hypotenuse, we have that the length of side A is: 
<h3>What are the relations in a right triangle?</h3>
The relations in a right triangle are given as follows:
- The sine of an angle is given by the length of the opposite side to the angle divided by the length of the hypotenuse.
- The cosine of an angle is given by the length of the adjacent side to the angle divided by the length of the hypotenuse.
- The tangent of an angle is given by the length of the opposite side to the angle divided by the length of the adjacent side to the angle.
From the information given, we can build the following relation:
cos(A) = a/c.



More can be learned about relations in a right triangle at brainly.com/question/26396675
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Answer: A)
Step-by-step explanation: