By rearranging x = 7y - 5 to make y the subject, we get
x + 5 = 7y ( By transposition method )
or, 
<h2>Answer:</h2>

Since we are given with the identity of the chemical as Carbon-14, we obtain the half-life of the chemical from a reliable source and get a value of 5730 years. The equation that we are going to use for this item is,
A(t)/A(0) = (0.50)^(n/5730)
where A(t) is the current amount, A(0) is the initial amount and n is the number of years. We know from the given that the ratio of A(t) and A(0) is equal to 0.63. Substituting this to the given,
0.63 = 0.50^(n/5730)
n = 3819.48
Thus, the sample is approximately 3819.5 years old.
A negative number wouldn't be reasonable in investments because when you invest you are adding money to something. If you invest you aren't removing anything so there can't be negative numbers.
The dog weighs 99 ounces more than the cat. you just have to convert to ounces then subtract.
20p + 9t = 44.4
Subtract 9t from both sides:
20p = 44.4 - 9t
Divide both sides by 20:
p = 2.22 - 0.45t