Answer :
2 to the second power is 4
4 to the second power is 16
4+16 = 20
100- 20 = 80
80 divided by 2 is 40
Ans: 40
Tip: If your not sure whether the answer is right or not, plug it back into the equation
2 x 2 = 4 + 4 x 4 = 16
4 + 16
= 20 + 2x = 100
(x = 40)
2 x 40 = 80 + 20 = 100.