You add two equations together to eliminate a variable. This particular problem is nice, because it's already setup to eliminate X.
3x - 4y = 9
<span>-3x + 2y = 9
</span>
When we add these two together, 3x - 3x cancels each other out, leaving us with 0x, or nothing.
We continue with -4y + 2y (leaves us with -2y) and 9+9 (18).
-2y = 18
18/-2 = -9.
Now we have y = -9, and we can go back into the problems to solve for x.
<span>3x - 4(-9) = 9
</span>
3x + 36 = 9.
3x = -27
x = -9.
Confirm with the final equation:
-3(-9) + 2(-9) = 9
27 - 18 = 9
9 = 9 --- Confirmed.
Answer:
Please read the answers below.
Step-by-step explanation:
Let's calculate the four means between 100 and 135, this way:
1. Arithmetic mean:
(100 + 135)/2 = 117.5
2. Weighted mean:
We will assign equal weight to both numbers : 5
(100 * 5 + 135 * 5)/10 = (500 + 675)/10 = 1,175/10 = 117.5
3. Geometric mean:
√100 * 135 = √13,500 = 116.2 (Rounding to the next tenth)
4. Harmonic mean:
2/(1/100 + 1/135) = 2/(0.01 + 0.0074) = 114.9 (Rounding to the next tenth)
Answer:
Chips = 14
Pretzel = 14
Cookie = 8
Popcorn = 13
Question Mark = 222
Step-by-step explanation:
First Equation:
Chips + Pretzel + Chips = 42
Third Equation: Chips = Pretzel.
This means that
Pretzel + Pretzel + Pretzel = 42
Pretzel = 
Chips = Pretzel
Chips = 
Second Equation:
Cookie + Chips + Cookie = 30
We know that Chips = 14.
Cookie + 14 + Cookie = 30
Subtract 14 on both sides:
Cookie + Cookie = 16
Cookie = 
.
Fourth Equation:
Cookie + Cookie + Popcorn = 29
We know that Cookie = 8.
8 + 8 + Popcorn = 29
16 + Popcorn = 29
Subtract 16 on both sides:
Popcorn = 13.
Question Mark:
(Popcorn + Popcorn) 
Cookie + Chips = (13 + 13) 8 + 14 = 26 8 + 14 = 
Answer:
72
Step-by-step explanation:
45% did not get shiped so 160*.45=72
