Question

Pieter wrote and solved an equation that models the number of hours it takes to dig a well to a level of 72 feet below sea level. 7h – 5(3h – 8) = –72

Which statement is true about Pieter’s solution?
1. It cannot be a fraction or decimal because the depth of the well is a whole number.
2.It must be a positive number since it represents a number of hours.
3. It must be a negative number because the depth is below sea level.
4.It cannot be greater than –72 because that is the depth of the well.

Answer 1

the answer is B It must be a positive number since it represents a number of hours.

Answer 2

Option B is correct

It must be a positive number since it represents a number of hours.

Explanation:

As per the statement:

Pieter wrote and solved an equation that models the number of hours it takes to dig a well to a level of 72 feet below sea level.

Given the equation as:

`7h-5(3h-8) = -72`

Using distributive property,
`a\cdot (b+c) = a\cdot b+ a\cdot c`

`7h-15h+40 = -72`

Combine like terms;

`-8h+40 = -72`

Subtract 40 from both sides we have;

`-8h= -112`

Divide both sides by -8 we have;

h = 14 hours

Therefore, the statement is true about Pieter’s solution is, It must be a positive number since it represents a number of hours.