Question

Mr. Mole left his burrow and started digging his way down.

B(t) models Mr. Mole's depth relative to the ground (in meters) after t minutes.

How far below the ground is Mr. Mole after 5 minutes?

B(t) = -2.3t - 7

Answer 1

What you do is you take -2.3t replace t with 5 multipy -2.3 and 5 to get -11.5 then you subtract 7 and get -18.5

Answer 2

18.5 meters

Explanation:

To find the value of the depth in meters, after mr. Mole had been digging for 5 minutes, t should be replaced with 5 in the formula.

`B(t)=-2.3t-7\\B(5)=-2.3(5)-7\\B(5)=-11.5-7\\B(5)=-18.5`

The value is negative, because Mr. Mole is digging downward. That means that after 5 minutes Mr. Mole had dug 18.5m downward.