Does anybody know what the missing side lengths are?!

x√3 = 5√ 3

x = 5√ 3 / √ 3

x= √ 3(5√ 3 / √ 3)

x= 15/3

b= 5

5x2 =10

a=10 and b=5

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value