Question

2x+4y=-5
2x-y=7

Answer 1

The way I learned to do these is to combine like terms.

Answer 2

ok i need help with these i can do some of them but when they add more number to it i get messed up

Answer 3

There are several ways to proceed.

Multiply the second by -1, giving -2x + y = -7, then simply add the two equations, combining like terms as you go.

See if that leads you anywhere useful.

Answer 4

ok

Answer 5

What will be the result...waiting...much excitement...!!!

Answer 6

ok hold on sec

Answer 7

ok so far i have gotten x=-1

Answer 8

That's a very odd result if you followed my instructions. You should get a value for 'y' first. What happened after you added the equations?

2x+4y=-5
-2x + y = -7

Answer 9

ok after i add i came up wiht 2x+8+28=-5

Answer 10

??? How did you do that?

2x + (-2x) - 0
4y + y = 5y
-5 + (-7) = -12

You shoudl get 5y = -12

Answer 11

ok the way your showing me is not been shown to me before

Answer 12

Were you solving one equation for 'y'?

Answer 13

yeah i understand that but what your showing and telling my teacher has not shown me this

Answer 14

No worries. Like I said up front. there are several ways to proceed. I was trying to show you"elimination". It's perfectly fine to use "substitution".

1) 2x+4y=-5
2) 2x-y=7

Solve Equation 2 for y, giving: y = 2x - 7.
Sunstitute this value for 'y' in Equation 1, giving 2x + 4(2x-7) = -5

Expand 2x + 8x - 28 = -5
Combine like terms 10x = -5 + 28 = 23
Solve for x, x = 23/10

Answer 15

hold on sec checking something

Answer 16

That's 'x'. Now you need to use that value to find 'y'.

Answer 17

okay i'm doing this math on my math lab and i was doing what you showed me and it still said was wrong

Answer 18

I really don't like thise thing. Too many format variations.

23/10 = 2 and 3/10 = 2.3

What did you get for y?