x biêt: b) 5^x+1-5^2=2^2.5^2

1. **Rewrite the equation:** $5^{x+1} - 25 = 4(25)$<br />2. **Simplify:** $5^{x+1} - 25 = 100$<br />3. **Isolate the exponential term:** $5^{x+1} = 125$<br />4. **Rewrite 125 as a power of 5:** $5^{x+1} = 5^3$<br />5. **Equate exponents:** $x+1 = 3$<br />6. **Solve for x:** $x = 2$<br />