The tables show some input and output values:

table a
input output
1 7
2 7
2 9
4 5
table b
input output
6 1
7 3
8 2
9 5

which tables represent functions?
only a
only b
both a and b
neither a nor b

Need ! give step by step solutions on how to solve number one [tex]\frac{9-2\sqrt{3} }{12+\sqrt{3} }[/tex] number two [tex]x+4=\sqrt{13x-20}[/tex] number three (domain and range) [tex]f(x)=2\sqrt[3]{x} +1[/tex]

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

Asap! i'm not good math and i'm lost.