Solve the system by substitution :
y=2x+2
y=3x
a.) (3,9) b.) (1,4)
c.) (-2,-4)

So since we already have one of the unknowns equaling something, we start by substituting...

y= 3x so let's substitute 3x into the first equation where the y is...

y = 2x + 2
3x = 2x + 2
subtract 2x from each side
x = 2

So now we know x = 2 So we can now substitute it back into the equation but for x this time...

y = 2x + 2
y = 2(2) + 2
y = 4 + 2 = 6

So our solution set is

(2, 6)

You can check it by substituting x and y into both of the equations to see if you have a true statement...

y= 2x + 2
6 = 2×2 + 2
6 = 6

y = 3x
6 = 3×2
6 = 6

Both true so it checks!

*note- I noticed that my solution was not one of your options, but if you substitute the available option that you gave into the equations none of them work, so take a look at your possible answers and see if you didn't leave something out. ;)