Skip to main content
← Back to archive

Problem #29 · August 25, 2026

Powers and roots

If 5x53=57\dfrac{5^{x}}{5^{3}} = 5^{7}, find xx.
  1. A44
  2. B2121
  3. C1010
  4. D77
  5. E3535

WORKED EXAMPLE

Solution

When dividing, subtract the exponents: 5x53=5x−3\dfrac{5^{x}}{5^{3}} = 5^{x-3}. Thus, 5x−3=575^{x-3} = 5^{7}, which gives x−3=7x - 3 = 7, so x=10x = 10.
Solve today's problem