substitution method

Question

Use the substitution method to solve the system of equations. Enter your answer as an ordered pair.

3x + y = 10
y = x - 2

Answer 1

Ok, so for this substitution the best thing to substitute is the y, because they already give you y=x-2

so then your other equation with the substitution would be 3x + x - 2 = 10

then solve for x

 

 

for example:

4x + y = 9

y = x - 1

so: 4x + x - 1 = 9

combine: 5x - 1 = 9

5x = 9+1 --> 5x = 10

x=2

then use y = x-1 --> y = 2-1

y = 1

then plug in the numbers to see if this works:

1 = 2 - 1

4(2) + 1 = 9

now try with your equation! you can do it!