x-2y=16 x-y=-8

Question

Solve the system equation

Answer 1

x - 2y = 16             eq1

x - y = -8               eq2

 

We can either use the substitution method or the elimination method.  Since the coefficient of x in both equations is 1, we can use the elimination method by subtracting eq2 from eq1.  This will eliminate the x terms.

 

-y = 24

 

y = -24

 

 

Next, substitute this value of y into eq1 to solve for x.

 

x - 2(-24) = 16

x + 48 = 16

x = -32

 

The solutions are

 

x = -32

y = -24

Answer 2

Two equations with two unknowns.

 

The way to solve these is to solve one (the simplest) for either x or y, and then inputting that value into the second equation.  Like so.

 

x - y = -8

x = -8 + y

x = y - 8

 

Now put y-8 in place of the x in the other equation, so

 

x - 2y = 16

(y-8) -2y = 16   Since y-2y = -y and 16+8 = 24

 

-y = 24

y=-24

 

Go back to the first equation to get x:

 

since x-y=-8

x-(-24) = -8

x= -32