Solve the system of equations by substitution. What is the solution for x?
2x + y = 1
4x + 2y = -2

A) x = 0
B) x = 2
C) There is no x value, as there is no solution.
D) x can be any value, as there is an infinite number of solutions.

Question

Solve the system of equations by substitution. What is the solution for x?
2x + y = 1
4x + 2y = -2

A) x = 0 
B) x = 2
C) There is no x value, as there is no solution.
D) x can be any value, as there is an infinite number of solutions.

anonymous · Answer

$2x+y=1\implies y=-2x+1$ so plug that in to the second equation $$4x+2y=-2\4x+2(-2x+1)=-2\4x-4x+2=-2\\color{red}{2\ne-2}$$oops -- we derived a falsehood by assuming there was a solution, so we can conclude there is no such solution $(x,y)$ satisfying both equations

anonymous · Answer

@oldrin.bataku so A or C?

anonymous · Answer

well clearly not A as that suggests there is a solution. there are no solutions