Help with solving a system?

Question

I need help with this problem, can anyone explain how to do it?

-----Solve the system.

3x+4y=-3

2x+y=8

It's all one problem, I don't have a clue where to begin. Thanks for anything at all, it'll bring me one step closer haha.

Answer 1

Here it is:

3x + 4y = -3

2x + y = 8

First eliminate x or y so that one of them (x or y) will be by itself. I choose  4 then I eliminate y by multiplying -4 to 2x + y = 8. (By the way, Capital X means to multiply.)

3x + 4y = -3

(2x + y = 8) X -4

Then you may eliminate y.

3x + 4y = -3

-8x - 4y = -32

--------------------

-5x = -35

Divide both sides by -5 so that x will be by itself.

x = 7

After you got x, you need to find y. You can find y by putting x = 7 to one of the equation.

2(7) + y = 8

Multiply 2(7) and subtract it to both sides leaving y.

y = -6

Final answer: x = 7 and y = -6 or (7, -6).

To double check, put x = 7 and y = -6 to both equations and

Hope this helps. =)

Answer 2

the easiest way is to use the substitution method on this problem

if you notice, equation 2 is almost solved for y

2x+y=8

y=8-2x     subtraction prop.

now substitute (8-2x) for y in the first equation:

3x+4(8-2x)=-3

and solve it

3x+32-8x=-3

-5x+32=-3

-5x=-35

x=7

Answer 3

In your case . . . x = 7, y = -6.

Basis:

(1) Begin by solving for y in the 2nd expression,

i.e., y =  8 - 2x

(2) Next, substitute this for y in the 1st expression,

i.e., 3x + 4(8 - 2x) = - 3

(3) Multiply out the 2nd term on the left side and collect like terms to

find that 3x + 32 - 8x = -5x + 32 = -3

(4) Solve for x by subtracting 32 from both sides and then dividing both

sides by (-5) to obtain

x =  -35/-5 = +7

(5) Finally, plug this value of x into either of the original expressions to

find y:

i.e., y = 8 - 2*7 = -6, or y = (-3 - 3*7)/4 = -6

Answer 4

3x+4y=-3

2x+y=8

2x+y=8 -> y=8-2x

3x+4(8-2x)= -3 = 3x+32-8x

-35 = -5x

x = 7

y = 8 - 2(7)

y = -6

Answer 5

You can use the Substitution Method:

http://www.mathclues.com/MSubstitutionMe...

or you can use the Addition Method (I'd recommend):

http://www.mathclues.com/MAdditionMethod...

Hope this helps you!  Please email anytime for further questions.