ANSWER
The greatest common factor is 5b.
EXPLANATION
The first expression can be rewritten as
[tex]35 {b}^{2} = 5 \times 7 \times {b}^{2} [/tex]
The second expression is rewritten as
[tex]15 {b}^{3} = 3 \times 5 {b}^{3} [/tex]
The third expression is
[tex]5b = 5 \times b[/tex]
The greatest common factor is the product of the least powers of the common factors.
[tex]GCF=5 \times b = 5b[/tex]
