answer needed with explanation

Answer:
75 is the greatest
Step-by-step explanation:
a and b have to be either 5 or 7 and if you do 10 × 7 + 5 it will be the greatest number
Answer:
[tex]a \: and \: b \: must \: be \: highest \: \\ so \: take \: a = 7 \: and \: b = 5 \: \\ because \: tey \: are \: the \: highest \: prime \: number \\ then \: n = 10a + b \\ n = 10 \times 7 + 5 \\ = 70 + 5 = 75 \\ thank \: you[/tex]