Answer:

Step-by-step explanation:
Since we know -7x=y we use the substitution method and plug it in the top equation.



or x=-2/3
Then plug it back in the the bottom equation

y=14/3
Answer: 4. -12
4. 9
6.17
Step-by-step explanation:
There are 1000 millimetres in a litre, so 1800 ml is 1.8 litres. 3-1.8 is 1.2.
90%
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Answer:
$9.80
Step-by-step explanation: