Answer:
Step-by-step explanation:
[tex]\tt 5ab-b, \: when\: a=4\: and \:b=9[/tex]
[tex]\tt 5(4)(9)-(9)[/tex]
[tex]\tt \:5\times 4\times 9-9[/tex]
[tex]\tt 180-9[/tex]
[tex]\tt 171[/tex]
Hope it helps! :)
