Question

Can someone solve these simultaneous equations and explain the way to do this easily:

3x+y=-4
3x-4y=6


Thanks a lot.

Answer 1

The easiest way to solve this system of equations is by elimination. Both equations have a 3x term, so we can basically subtract the equations to cancel the 3x. Then we will be left with a single variable to solve for.

(3x + y = -4)
-(3x -4y = 6)

Distribute the negative:

(3x + y = -4)
(-3x + 4y = -6)

Now add the equations together term by term:

0x + 5y = -10

5y = -10

y = -2

Plug y = -2 into either equation to find x.

3x + (-2) = -4

3x = -2

x = -2/3

So the answer as an ordered pair is (-2/3, -2)