Nathan B. answered 01/11/18
Tutor
5
(20)
Elementary and Algebraic skilled
Let Z = Zi, T = Tina, and M = Mom
Here's what we know:
Z + T = 19 (Zi and Tina together made 19 points)
M + T = 14 (Mom and Tina together made 14 points)
T = M + Z (Tina made as many points as Mom and Zi together)
We have a value for T, so let's plug it into the two equations:
Z + M + Z = 19
2Z + M = 19
M + M + Z = 14
2M + Z = 14
From here, we can use the elimination method to remove one of the variables by multiplying one of the equations by -2, or by isolating one of the variables. I'll be using elimination in this case.
-2(2M + Z = 14) → -4M - 2Z = -28
2Z + M = 19
-2Z - 4M = -28
----------------------
-3M = -9
Divide both sides by -3:
M = 3
Now that we know M, we can solve for Z:
2M + Z = 14
2 * 3 + Z = 14
6 + Z = 14
Z = 8
T = M + Z
T = 3 + 8
T = 11
Now to check:
T + Z = 19
11 + 8 = 19
19 = 19
M + T = 14
3 + 11 = 14
14 = 14