For the given vectors
and 
The dot product of vectors a and b is defined as = 
So, 

= -16+12
= -4
8x - 2y = 48, y =4
8x - 2(4) = 48
8x - 8 = 48
8x = 48+8
8x = 56
x = 56/8 = 7
x = 7
6√5 - 4√3-
i took the test but sorry if its wrong
If the area of the room is 9x2 − 6x + 1 square feet, then the
length of one<span> side of the room is <span>(3x − 1) feet. </span></span>The correct answer between
all the choices given is the third choice or letter C. I am hoping that this
answer has satisfied your query and it will be able to help you in your
endeavor, and if you would like, feel free to ask another question.
First, make up some variables to represent the number of Girls and Boys in the choir.
B = number of boys
G = number of girls
You know that there are 4 times as many girls in the choir as boys. Therefore, the equation you can write is:

If you cross-multiply, then you get the simplified equation:
G = 4B
Intuitively this makes sense since if you multiplied the number of boys in the class by 4, that would be equal to the number of girls you have.
Now, we know that the total class size is 60. So girls plus boys equals 60:
G+B = 60
To solve the equation, replace the G in this equation with the replacement you found before, 4B.
G + B = 60 -->
4B + B = 60 -->
5B = 60 -->
B = 12
However, you are trying to find the number of girls, so plug the answer back into your equation.
G + B = 60 -->
G + 12 = 60 -->
G + 12 -12 = 60 - 12 -->
G = 48
The number of girls you have is 48.