Which system has infinity many solutions?

Question

1)y=2x+6
y-8x=21

2) 4x-4y=4
x-y=1

3) 4x+2y=5
x-2y=9

4) none

Answer 1

2)
x and y can increase infinitely as long as the value of x is 1 more than the value of y

Answer 2

A system has an infinite number of solutions if the two equations are the same but multiplied by a constant.

eqs 2 is just that

if you multiply both sides of x-y=1 by 4,
you get 4x-4y=4.

Since same equation infinite number of solutions.

Answer 3

1) you can find a soln for x and y because you have two eqns and two unknowns
2) only one equation, the second is the same as the first; therefore, there an infinite number of solutions
3) answer is same as 1) for the same reason
4) because of 2), this cannot b

The answer is 2)

Answer 4

2) 4x-4y=4 divide by 4
x-y=1

the equations are the same.

Answer 5

Infinitely many solutions means that the two equations represent the same line. Check to see if that is true. (I see one)