<u><em>Answer:</em></u>
<u><em>Explanation:</em></u>
<u>Part 1: Solving for m</u>
<u>We are given that:</u>
E = mc²
To solve for m, we will need to isolate the m on one side of the equation
This means that we will simply divide both sides by c²
<u>Part 2: Solving for c</u>
<u>We are given that:</u>
E = mc²
To solve for c, we will need to isolate the m on one side of the equation
This means that first we will divide both sides by m and then take square root for both sides to get the value of c
<u>Part 3: Solving for E</u>
<u>We are given that:</u>
m = 80 and c = 0.4
<u>To get the value of E, we will simply substitute in the given equation: </u>
E = mc²
E = (80) × (0.4)²
E = 12.8 J
Hope this helps :)