Question

Solve the following system of equations.

-2x + y = 1
-4x + y = -1

A) (3,1)
B) (-1,3)
C) (-1,-3)
D) (1,3)

Answer 1

Hi Brainiac

-2x+y=1

-4x+y=-1

We need to solve -2x+y=1 for y

Now let's start by adding 2x to both sides

-2x+y+2x=1+2xy=2x+1

Substitute 2x+1 for y in -4x+y=-1

-4x+y=-1

-4x+2x+1=-1

-2x+1=-1

Add -1 to both sides

-2x+1-1=-1-1

-2x=-2

Now divide both sides by -2 so we can fine the value for x

-2x/-2= -2/-2

x=1

The last step is to substitute 1 for x in y=2x+1

y=2x+1

y=(2)(1)+1

y= 2+1

y= 3

Answer : D , (1,3)

Good night :)