In:mi
2 = 30
x = 120
2/30=x/120
(Cross Multiply)
30x= 240
30x/30=240/30
X=8
In system A, the first equation multiply by 4
8x - 4y = 12 (1st)
3x + 4y = 10 (2nd)
--------------------add
11x = 22
So answer is B.
Carmen has given 6 coins to her brother<span />
The difference of the expression
is 
<h3>How to determine the difference?</h3>
The expression is given as:

Factor the denominators of the expressions:

Apply the difference of two squares to x² - 9

Take LCM

Hence, the difference of the expression
is 
Read more about expressions at:
brainly.com/question/723406
#SPJ4