Question

4x – y = 5
3x + y = 16 (4, 4) (3, 5) (4, 11) (3, 7)

Answer 1

4x - y = 5

3x + y = 16

rearrange the first equation so you can substitute it into the second:
y = 4x - 5

3x + (4x - 5) = 16
3x + 4x - 5 = 16
7x = 16 + 5
7x = 21
x = 21/7
x = 3

4(3) - y = 5
12 - y = 5
-y = 5 - 12
-y = -7
-1(-y = -7)
y = 7


the answer is (3, 7)

hope this helps :)

Answer 2

Since one equation has a positive y and the other a negative y we can simply add the two equations together to solve for x...

(4x-y=5)+(3x+y=16)

7x=21,

x=3, now you can use either original equation to solve for y...

3x+y=16 becomes:

3(3)+y=16

9+y=16

y=7

So the solution is the point (3,7)