subtitution and Elimination #4

Question

y=x+1

y=2x+2

 

 

x+y=5

2x-3y=5

 

 

 

x+y=0

5x+y=4

Answer 1

1- y = x + 1

2- y = 2x + 2

Let's substitute equation 1 on 2

in other words, wherever y is, let's write x + 1 instead

x + 1 = 2x + 2

Let's subtract x from both sides

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

1 = x + 2

Let's subtract 2 from both sides

1 - 2 = x + 2 - 2

In order to find the value of y, let's substitute x on either equation 1 or 2

In this example, let's use equation 1

y  = x + 1

y = -1 + 1

y = 0

It's always good practice to check the results in both equations to make your work is correct