Differentiating both sides of

with respect to <em>x</em> yields (using the chain rule)

Solve for d<em>y</em>/d<em>x</em> :

The answer is then D.
Easy, just write out the multiple of the numbers.
4: 4,8,12,16,20,24,28,32,36,40,44,48,52,56,60
7: 7,14,21,28,35,42,49,56,63,70
Etc.
But a few common multiples:
28,56,84,112,140
These are the first 5 common multiples of 4 and 7.
The correct answer is choice d.....
Answer:
$1.80
Step-by-step explanation:
9x0.2=1.80
He should leave 1.80 as a tip.