Answer: 57
Step-by-step explanation:
Given: a is a multiple of 456
Let [tex]a = 456 x[/tex]
Then, expression [tex]3a^3+a^2+4a+57 =3(456x)^3+(456x)^2+4(456x)+57[/tex]
Since 456 = 57 x 8
Then, [tex]3(456x)^3+(456x)^2+4(456x)+57=3(57\times 8x)^3+(57\times 8x)^2+4(57\times 8x)+57[/tex]
[tex]=3(57)^3\times (8x)^3+(57)^2\times (8x)^2+4(57)\times (8x)+57[/tex]
Taking 57 out as common
[tex]=57[3(57)^2\times (8x)^3+(57)\times (8x)^2+4\times (8x)+1][/tex]
Now, the greatest common divisor of [tex]a = 456 x[/tex] and [tex]3a^3+a^2+4a+57=57[3(57)^2\times (8x)^3+(57)\times (8x)^2+4\times (8x)+1][/tex] is 57.
Hence, the greatest common divisor of 3a^3+a^2+4a+57 and a is 57.
