Answer:
[tex]10[2k+5][/tex]
Step-by-step explanation:
we have
[tex]20k+50[/tex]
Decompose each number in prime factors
we know that
[tex]20=(2^{2})(5)[/tex]
[tex]50=(2)(5^{2})[/tex]
substitute
[tex](2^{2})(5)k+(2)(5^{2})[/tex]
Factor (2)(5)
[tex](2)(5)[(2)k+(5)]\\10[2k+5][/tex]