find k if 5^k+ 5^k-1= 750

Dear Student,

5^{k} + 5^{k - 1} = 750 \Rightarrow 5^{k} + 5^{k - 1} = 5^{3} \times 2 \times 3 \Rightarrow 5^{k} + 5^{k - 1} = 5^{3} \times 6 \Rightarrow 5^{k} + 5^{k - 1} = 5^{3} \times (5 + 1) \Rightarrow 5^{k} + 5^{k - 1} = 5^{3} \times 5 + 5^{3} \Rightarrow 5^{k} + 5^{k - 1} = 5^{3 + 1} + 5^{3} \Rightarrow 5^{k} + 5^{k - 1} = 5^{4} + 5^{3} C o m p a r i n g t h e q u a n t i t i e s w e g e t k = 4

Regards,

find k if 5k + 5k-1 = 750