Martina went shopping. She spent a fifth of what she had in her wallet and then a fifth of what remained. In all she spent $36. How much did she start with?

For what values of p could the expression 100 divided by p-squared -16 not be evaluated. Explain your answer.

Thanks

let the amount she had be $x

then she spent (1/5) and (1/5)(4/5)x

the sum of that is 36.
Can you take it from there?

for your second part

remember that the only way that 100/(p^2-16) cannot have a value is when we divide by zero.

so when is p^2 - 16 = 0???

i have a homework problem:

Sierra -- please click Post a New Question and type your problem there.

To find out how much Martina started with, we can follow these steps:

1. Let's assume Martina started with x dollars in her wallet.
2. She spent a fifth (1/5) of what she had, so she spent (1/5) * x dollars. After this expense, she has (4/5) * x dollars remaining.
3. Then she spent another fifth (1/5) of what remained, which is (1/5) * (4/5) * x dollars. After this expense, she has (4/5) * (4/5) * x dollars remaining.
4. The total amount she spent is $36. So, we can set up the equation: (1/5) * x + (1/5) * (4/5) * x = 36.
5. Simplifying the equation, we have: (1/5) * x + (4/25) * x = 36.
6. Combining the like terms, we get: (9/25) * x = 36.
7. To solve for x, we can multiply both sides of the equation by (25/9): x = 36 * (25/9).
8. Evaluating the expression, we find: x = 100.

Therefore, Martina originally had $100 in her wallet.

Regarding the expression (100 / p^2) - 16:

To evaluate this expression, we need to ensure that the denominator (p^2) is not equal to zero. Because division by zero is undefined in mathematics. So, in order to find the values of p for which the expression cannot be evaluated, we set the denominator equal to zero and solve for p:

p^2 = 0

Taking the square root of both sides, we get:

p = 0

Therefore, the expression (100 / p^2) - 16 cannot be evaluated when p equals zero. For all other values of p, the expression can be evaluated.