Algebra - Substitution Question?

A+B+C=1
A+C= -1/2
A-B+C= -7

What are the values of A, B, and C?

Subtract the third equation from the second and you get

B = 6 1/2
Subtract the second from the first and you get B = 3/2

Both cannot be true, so there is no solution.

that's what i got too

To solve this system of equations using substitution, we'll start by solving one equation for a specific variable, and then substitute that expression into the other equations. Let's solve the second equation for A:

A + C = -1/2

By isolating A, we can subtract C from both sides:

A = -1/2 - C

Now, substitute this expression for A in the first and third equations:

1) A + B + C = 1
(-1/2 - C) + B + C = 1

2) A - B + C = -7
(-1/2 - C) - B + C = -7

Now, simplify both equations:

1) -1/2 - C + B + C = 1
B - 1/2 = 1

2) -1/2 - C - B + C = -7
-B - 1/2 = -7

To solve these equations, isolate B in equation 1:

B = 1 + 1/2

B = 3/2

Now, substitute this value of B into equation 2:

-(3/2) - 1/2 = -7

-4/2 = -7

-2 = -7

This is not a true statement, which means there is no solution. The system of equations is inconsistent, and there are no values for A, B, and C that satisfy all three equations simultaneously.

Hence, there are no values for A, B, and C.