Question

10x - 10y = 1
x = y - 3
Solve the system of equations by substitution.


(-29/20, 31/20)
(1/2, 2/5)
no solution
coincident

Answer 1

Put x = y - 3 in the first equation and solve (or try to solve) for y.

If you try the substitution, you will quickly reach a conclusion.

Answer 2

Add the 1st equation to the -10 times the second, I get for the x's 0x.

For the y parts, I get 0y.

For the constants I get 31.

That leaves me with, 0y=31, which means that y is undefined.

These equations are parallel and never intersect because they have the same slope but have different y-intercepts.

There is no solution:
http://www.wolframalpha.com/input/?i=10x+-+10y+%3D+1%2C+x+%3D+y+-+3

Answer 3

^^^ Solving by elimination.
Problem says solve by substitution.

Answer 4

You know what x is, so plug that bad boy into the other equation just like last time.

Answer 5

@ranga is correct, just sub like instructions say