Question

Help! i just need the answers. maybe some explanations would be good too :)

Answer 1

For Number one: -xy + 2x = 20, x = 5

To solve this, all we need to do is plugin 5 for every place we have x. So...

- (5)y + 2(5) = 20

-5y + 10 = 20

-5y = 10

y = -2

For number two: 4x - 3y - 10 = 1, x = -1

To solve this, we need to plugin -1 for all of the x variables. So...

4 (-1) - 3y - 10 = 1

-4 - 3y - 10 = 1

-14 - 3y = 1

-3y = 15

y = -5

For number three: 5x + 7y = -1, x = 4

We need to plugin -4 for all of the x variables. So...

5 (4) + 7y = -1

20 + 7y = -1

7y = -21

y = -3

For number four: x = 6 + xy, x = -3

Same as the other ones, just plugin -3 for all of the x variables. So...

-3 = 6 + (-3)y

-3 = 6 - 3y

-9 = -3y

3 = y

I hope this helps :)