It is d Ik Bc Ik don’t ask why just know it’s d
R=$350, I=0.05, n=15
A = 350 (1+0.05)^15 = 350(1.05)^15 = 350 (2.0789)=727.62 <- Answer
The constant variation k is 12
√5 = 5^(1/2)
Multiplying two number with the same base has as result a number with the same base and the sum of the exponents so:
1/2 + 3 = 7/2
which means
5^3 x 5^(1/2) = 5^(7/2)
You would multiply the power by the powers of both exponents
2 × 3 = 6 so a^6
3 × 4 = 12 so b^12
Answer is
a^6b^12