Maths Gcse Identity help

Please can you explain how to solve the following question, thank you

The identity a(x+2)-x≡3x+8 is true for all values of x. Find the value of a.

Reply 1

Xzylem

expand the brackets to ax + 2a - x ≡ 3x + 8

if you separate the integers and x terms
ax - x = 3x
and
2a = 8

you can solve either of these to get a = 4

Reply 2

hi1415

Original post by Xzylem

expand the brackets to ax + 2a - x ≡ 3x + 8

if you separate the integers and x terms
ax - x = 3x
and
2a = 8

you can solve either of these to get a = 4