A number divided by 5 is 3 more than -6 A)-45 B)-30 C)-15 D)-5
2 answers:
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Answer:
Step-by-step explanation:
The half life is the amount of time it takes a substance to decay to half of its original amount.
Since the radioactive substance has a half life of 1000 years, there will be half of it left after 1000 years.
So, the fraction that will be left after 1000 years is
(x, y) = ( ,
)
given the 2 equations
5x - 3y - 10 = 0 → (1)
x + y - 7 = 0 → (2)
rearrange (2) to obtain y in terms of x
y = 7 - x → (3)
Substitute y = 7 - x into (1)
5x - 3(7 - x) - 10 = 0
5x - 21 + 3x - 10 = 0
8x - 31 = 0 ( add 31 to both sides )
8x = 31 ( divide both sides by 8 )
x =
Substitute this value into (3) for y
y = 7 - x = -
=