Confused on a stats problem!

So the problem is: If the r.v. X is distributed as N(μ, σ ^2), identify the constant c, in
terms of μ and σ, for which:
P(X < c) = 2 − 9P(X > c).
Now, I solved and got so far as -7 + 9(PX<= c); but the P(X<=C) is apparently 7/8 according to the answers in the book. How do they reach that conclusion? Please help!

P(X < c) = 2 - 9P(X > c)
Retain the constant on the right hand side
P(X < c) + 9*P(X > c) = 2
P(X < c) + P(X > c) + 8*P(X > c) = 2
Since P(X < c) + P(X > c) = 1, ----------- Eq (1)
1 + 8*P(X > c) = 2
8*P(X > c) = 2 - 1 = 1
P(X > c) = 1/8
On substitution in Eq (1)
we get P(X < c) + 1/8 = 1
= 1 - 1/8
= 7/8