Maths: How do you make 'a' the subject?

a)
ax = y
a = y/x

b)
a(p - 4) = q
a = q/(p - 4)

c)
ax + by = c
ax = c - by
a = (c - by)/x

d)
p(a + b) = c
a + b = c/p
a = c/p - b

e)
2a - 3m = 4a - 7
2a - 4a = 3m - 7
a(2 - 4) = 3m - 7
a = (3m - 7)/(-2)

f)
5b - 2a = 3c
2a = 5b - 3c
a = (5b - 3c)/2

I can't help, cos the other guy got it all correct. He's kinda good..... So I'm just here to get the 2 pts. sry. But at least u know that his answers are correct!!!!

Question a)
a = y / x

Question b)
a = q / (p - 4)

Question c)
ax = c - by
a = (c - by) / x

Question d)
p a + p b = c
p a = c - p b
a = ( c - p b ) / p

Question e)
7 - 3 m = 2 a
a = (7 - 3 m ) / 2

Question f)
5b - 3c = 2a
a = ( 5b - 3c ) / 2