Answer :

5(5a+3)=14a-29 -- expand brackets
25a+15=14a-29 -- subtract 15 and subtract 14a from both sides
11a=-44 -- divide by 11

a=-4
5(5a+3)=14a-29
5(5a)+5(3)=14a-29
25a+15=14a-29
-14a     -14a
11a+15=-29
      -15  -15
11a=-44
11a/11=-44/11
a=-4