In step 2 .. because when you multiple by -4 in step 1 , the equation in step 2 will be ( -4y =-16 + 8z)
I suppose you mean

Differentiate one term at a time.
Rewrite the first term as

Then the product rule says

Then with the power and chain rules,

Simplify this a bit by factoring out
:

For the second term, recall that

Then by the chain rule,

So we have

and we can simplify this by factoring out
to end up with

The value of 4 in 34,258 is 4,000 times the value of 4 in 47,163 is 40,000
40,000*4,000 is 160000000
You solve the problem and the answer is 982,810 :)
Answer:
a = 9
Step-by-step explanation:
a^2 = 41^2 - 40^2
a^2 = 1681-1600 = 81
a = 9