Choice B) Commutative Property is the answer
The commutative property of addition says that we can add two numbers in any order. For example: 2+3 = 5 and 3+2 = 5.
In general, the rule can be written as x+y = y+x. The x and y are simply placeholders for numbers. You can think of them as empty boxes to write a number inside. In this case, we have 7.2 for one of the boxes and -5.5 as the other value in the other box.
1 )
1st and 2nd equation (multiply 1st by -2 ):
-2x - 10 y + 8 z = 20
2 x - y + 5 z = -9
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- 11 y + 13 z = 11 / * ( -20 )
1st and 3rd:
- 2 x - 10 y + 8 z = 20
2 x - 10 y - 5 z = 0
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- 20 x + 3 z = 20 / * 11
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220 y - 260 z = -220
- 220 y + 33 z = 220
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z = 0, y = -1, x = - 5
2 )
2 x - y + 5 = -4
- 2 x + 3 y - 5 = - 10
Substitution: y = 2 x + 9
- 2 x + 3(2 x + 9 ) = -5
4 x = - 32, x = -8, y = -7, z = 5
3 )
x + y + z = 11
1.5 x+3 y +1.5 z = 21
x = 2 y
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3 y + z = 11 / * (-2)
6 y + 1.5 z = 21
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- 6 y - 2 z = -22
6 y + 1.5 z = 21
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-0.5 z = -1, z = 2, y = 3, z = 6
Answer: the store used 6 pounds of peanuts, 3 pounds of almonds and 2 pounds of raisins.
Answer:
He needs four packs.
Step-by-step explanation:
6*4=24 there is 23 so he will need 4 packs in total.
Answer:
x = 9.5y
Step-by-step explanation:
7 lawns = $66.50
1 lawn = $66.50 ÷ 7
= $9.50
You now know that for one lawn mowed, the amount of money earned is $9.50. Thus:
1x = 9.5y
x = 9.5y
