Answer:

Step-by-step explanation:
we know that
Using proportion

<u>ANSWER</u>

<u>EXPLANATION</u>
The given function is

We make the coefficient of
unity by factoring
out of the last two terms to obtain;

We now add and subtract half the coefficient of
multiplied by a factor of 6 to obtain;

We now factor 6 out of the last two terms to get;


The quadratic trinomial in the parenthesis is now a perfect square.

Hence the vertex form of the polynomial is

(y-2)4 + 21
You subtract two because the 21 accounts for it and then whatever you have left multiplied by 4 and added to 21 is the amount of years after conversion.
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Answer:
zero product property of multiplication
Step-by-step explanation:
step 2 is valid, because for the main expression in step 1 to be true, only one of the 2 factors need to be 0, as
0 × something is always 0.
therefore, it is sufficient to find the values of x that renders the expression of one factor to 0.