Answer:
Answer: a = 15/2 ,
Explanation:
Subtract 21 from both sides 16a+21 = 20a-9
16a + 21 -21=- 20a- 9 -21
Simplify the expression
16a + 21 -21=- 20a- 9 -21
16a=20a -30
Subtract 20a from both sides
16a=20a -30
16a - 20a = 20a -30 - 20a
Solution
a = 15/2