remember, you can do anything to an equation as long as you do it to both sides
we hate fractions so times both sides by 4
4A+8x-7x=8x+24a+8
combine like terms
4A+x=8x+24a+8
minus x both sides
4A=7x+24a+8
minus (24a+8) from both sides
4A-24a-8=7x
divide both sides by 7
[tex]\frac{4A-24a-8}{7}=x[/tex]
[tex]x=\frac{4A-24a-8}{7}[/tex]