AlgebraMultiple choice
posted by Kris on .
Hello,
I have some practice math I'm working through and I'm unsure about the answer. I will also put what I got. Thanks for the help.
1. Solve using any method and identify the system as consistent, inconsistent, or dependent.
2x+y=8
2x+2y=8
A.) (4,0); consistent/independent
B.) (4,0); consistent/dependent
C.) {(4,0  2x+y=8} ; consistent/dependent
D.) zero with a line through it;consistent
I thought C for this one.
2.) Solve the system using the elimination method. If the system is inconsistent or dependent, so state.
x2y+5z=1
x2y+3z=5
2x4y+10z=3
A) (5,3,2)
B) (5,4,1)
C) dependent
D) no solution, inconsistent
I got C for this one.
3.) Solve using any method and identify the system as consistent, inconsistent, or dependent.
0.2y=0.4x+0
0.8x0.4y=5
A.) zero with a line through it; inconsistent
B) zero with a line through it; consistent
C) zero with a line through it; dependent
D) Determination is not possible with the given information
I got A for this.

1. Should be C (IF not, then B)
2. D, if you multiply 1st equation by 2, try subtracting the third equation, and you get 0 = 5 or 0 = 1
3.
2y = 4x
8x4y=5
4y = 58x
4y = 8x5
2y = 4x  5/2
When minus the first equation from this, we get 0 = 5/2
So, A.