10(line)2-4a(line)=20

Question

Absolute value
How do I solve this equation?

Answer 1

Are you saying
|2-4a| = 20 ????

if so, then
2-4a = 20 or 2-4a = -20
-4a = 18 or -4a = -22
a = -9/2 or a = 11/2

Answer 2

sure