This is from Khan academy I have to attach a PNG if you can help me solve it! Thank you!

Step-by-step explanation:
[tex] \frac{5 {}^{ - 4x + 7} }{125 {}^{x} } [/tex]
[tex] \frac{5 {}^{ - 4x + 7} }{5 {}^{3x} } [/tex]
[tex]5 {}^{ - 4x + 7 - 3x} [/tex]
[tex]5 {}^{ - 7x + 7} [/tex]