Question

Solve by elimination or elimination with multiplication.
x - y = 3 and x + y = 7

Answer 1

1 -1 3
1 1 7

1 -1 3
0 2 4

1 -1 3
0 1 2

1 0 5
0 1 2

x = 5, y = 2

Answer 2

that makes no sense whatsoever....

Answer 3

Ok that process seems unclear to me also, but the goal here is to find an x and y for which both equations evaluate.

So read this question as "For what value of x and what value of y, gives 3 when you substract them (x-y = 3), and gives 7 when you add them (x+y = 7)?

Does that make sense?

Answer 4

This is a classic 'substitution equation.

x - y = 3 so
x = y + 3 so substitute x
x + y = 7 so
y + 3 + y = 7 so
2y = 7 -3
2y =4
y = 4/2
y = 2

x -y = 3
so x - 2 = 3
x = 2 + 3
x =5

Answer 5

make sense?

Answer 6

Nikkie that is not right, check again.

You're first saying x = 7 and y = 4, which would mean 7-4 = 3 ánd 7 + 4 = 7...

Answer 7

The x and y values are the same in both formulas. You use different ones.