3x+4y-3z=4;5x-y+2z=3;x+2y-z=-2 Solving Systems in three variables
1 answer:
Answer: x = 3, y = 1, z = 2
<u>Step-by-step explanation:</u>
EQ 1: x - y - z = 0
EQ 3:<u> -x + 2y + z = 1 </u>
y = 1
EQ 2: 2x - 3y + 2z = 7 → 1(2x - 3y + 2z = 7) → 2x - 3y + 2z = 7
EQ 3: -x + 2y + z = 1 → -2( -x + 2y + z = 1) → <u>-2x + 4y + 2z = 2</u>
y + 4z = 9
y = 1 ⇒ 1 + 4z = 9
4z = 8
z = 2
Input y = 1 and z = 2 into one of the equations to solve for x:
EQ 1: x - y - z = 0
x - (1) - (2) = 0
x - 3 = 0
x = 3
Check:
EQ 2: 2x - 3y + 2z = 7
2(3) - 3(1) + 2(2) = 7
6 - 3 + 4 = 7
3 + 4 = 7
7 = 7
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Answer:
Cost of a snack size bag of chips = $0.8
Cost of a water bottle = $1.6
Cost of a gallon of milk = $3.4
Step-by-step explanation:
Let the cost of water bottle = $a
Cost of 1 gallon milk = $b
and cost of 1 bag of chips = $c
So, cost of 4 gallons of milk, 6 bottles of water and 5 bags of chips = $(4b + 6a + 5c)
4b + 6a + 5c = 27.2 -----(1)
Cost of one water bottle = 2 × cost of one bag of chips
a = 2c -----(2)
A gallon of milk = cost of water bottle + $1.80
b = a + 1.8
From equation (2)
b = 2c + 1.8 -----(3)
Now we substitute these values from equations (2) and (3) in equation (1)
4(2c + 1.8) + 6(2c) + 5c = 27.2
8c + 7.2 + 12c + 5c = 27.2
25c = 27.2 - 7.2
c =
c = $0.8
From equation (2)
a = 2×0.8
a = $1.6
From equation (3)
b = 2(0.8) + 1.8
b = 1.6 + 1.8
b = $3.4
Therefore, cost of a snack size bag of chips = $0.8
Cost of a water bottle = $1.6
Cost of a gallon of milk = $3.4