Answer: i guess the problem is with P(x) => "x = 
", then P(x) is true if that equality is true, and is false if the equality is false.
so lets see case for case.
a) x = 0, and 
= 0. So p(0) is true.
b) x = 1 and 
= 1, so P(1) is true.
c) x = 2, and 
= 4, and 2 ≠ 4, then P(2) is false.
d) x= -1 and = 1, and 1 ≠ -1, so P(-1) is false.
The answer is x=5/8. The reason for this is when you divide it equal 0.625 then when you multiply that by 2 it equals 1.25. After you do that you add 5 which is 6.25. Now we divide 4/5 which is 0.8. Now, we multiply 6.25x0.8=5. 5-4=1. Therefore your answer is 5/8. Hope this helps :)
% increase = 100 - 85
--------- * 100
85
= 17.65
= 18 % to nearest per cent
