please!! yaa kaakk di bantuu

bila a*b = (a+b)^3 - (a^3 + b^3) / 3ab
maka nilai 5*2
= (5+2)^3 - (5^3 + 2^3) / 3*5*2
= 7^3 - (125 + 8) / 30
= 343 - 133 / 30
= 210 / 30
= 7
jawabnya : C. 7