Question

WILL GIVE BRAINLIEST!!!!!!! A boy had 20 cents. He bought x pencils for 3 cents each. If y equals the number of pennies left, write an equation showing the dependence of y on x. What is the domain of the function?

Answer 1

Answer:

$\displaystyle \text{Function: }{y=20-3x,\\\text{Domain: }(-\infty, \infty)\text{ or }\mathbb{R}$

Step-by-step explanation:

If the boy initially had 20 cents, then the total number of cents he will have left after purchasing $x$ pencils is equal to the total cost of the pencils subtracted from 20. The total cost of $x$ pencils, in cents, is equal to $3x$, since each pencil is 3 cents.

Therefore, the total amount, in cents, that the boy has left, $y$, is equal to $20-3x$:

$\displaystyle \text{Equation: }\boxed{y=20-3x}$

The domain of this function is $(-\infty, \infty)$ or all real numbers $\mathbb{R}$.