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?

Answer 1

Answer: h=-4

Explanation:

Answer 2

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

Explanation:

I got it right on EDG.

Simplifying

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

Reorder the terms:

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

7h + (-8 * -5 + 3h * -5) = -72

7h + (40 + -15h) = -72

Reorder the terms:

40 + 7h + -15h = -72

Combine like terms: 7h + -15h = -8h

40 + -8h = -72

Solving

40 + -8h = -72

Solving for variable 'h'.

Move all terms containing h to the left, all other terms to the right.

Add '-40' to each side of the equation.

40 + -40 + -8h = -72 + -40

Combine like terms: 40 + -40 = 0

0 + -8h = -72 + -40

-8h = -72 + -40

Combine like terms: -72 + -40 = -112

-8h = -112

Divide each side by '-8'.

h = 14

Simplifying

h = 14