Question

x + 3y = 7 x - 3y = 1 Solve the system of equations. A) x = 4, y = 1 B) x = 1, y = 4 C) x = - 2 3 , y = 3 D) x = 3, y = - 2 3

Answer 1

X+3y=7
x-3y=1
add them together

x+3y=7
x-3y=1 +
2x+0y=8

2x=8
divide 2
x=4
subsitute
x+3y=7
4+3y=7
subtract 4
3y=3
divid 3
y=1

x=4
y=1

answer is A

Answer 2

X + 3y = 7 
x - 3y = 1

x + 3y = 7
   - 3y    -3y

x = 7 - 3y

x - 3y = 1
7 - 3y - 3y = 1
7 -6y = 1
-7         -7

-6y = -6
y = 1

Now solve for x

X + 3y = 7
x + 3 = 7
x = 4

Now we have our values:-
x = 4 and y = 1

Answer: A) x = 4, y = 1