First one uses elimination, as you have already done, allowing you to find Y. You keep going and add the x’s and numbers together as well getting
6y = 12
Divide the 6
Y = 2
To find X just pick one of the ORIGINAL equations (doesn’t matter which) and plug in 2 for why and solve for x
Ex: 3x + 2(2) = 7
3x + 4= 7
Subtract 4
3x= 3
Divide 3
X = 1
Then check to see if it’s correct by plugging both in for the second equation.
-3(1) + 4(2) =5
5=5 both work
so your answer is (1,2)
For your second one you can solve by substitution or by elimination, however, because y is by itself substitution would be easier.
5x + 2y = 7
-4x + y = -16
Get y by itself for the second equation by adding 4x to each side (because 4x is negative and you need to cancel it) making:
Y= 4x - 16
you then replace this equation in where y is in the first one
5x + 2(4x - 16) = 7
Distribute the 2
5x + 8x - 32 = 7
Combine like terms (and add 32 to both sides)
13x = 39
Divide 13
X = 3
Go back to the ORIGINAL equations and replace x in any one.
5(3) -2y =7
15 - 2y =7
Subtract 15
-2y = -8
Divide - 2
Y=4
And check to make sure (3,4) is correct by plugging in
-4(3) - 4 = -16
-12 -4 = -16
-16 = -16
(3,4) works