Let's solve this system using elimination by addition/subtraction.
Note that if we mult. the first equation by 5, we get 20x + 15y = 70, and if we mult. the 2nd eqn by 3, we get 18x - 15y = 120.
Adding these two results together eliminates the y terms: 38x = 190. Then
x=5.
Subbing 5 for x in the 1st equation: 4(5) + 3y = 14
20 + 3y = 14
3y= -6
y = -2
Then the solution is (5,-2). Check this by subbing 5 for x and -2 for y in the 2nd equation. Is the second equation then true?