Answer: B. (6,4)
Find x for the 2nd equation
3x + 6y = 42
3x = 42-6y
x= (42-6y) / 3
Place the value of x in the first equation and find for y then.
4x - 3y= 12
4{(42-6y)/3} - 3y = 12
So the answer for y is 4
Now, you know the value of y is 4.
4x - 3*4 = 12
4x - 12 = 12
x= 12+12 /4
x= 6
So x is 6 and y is 4. So the answer is B.